feat: update solutions to lc problem: No.0990

yanglbme · yanglbme · commit 7efdc35a531f · 2022-03-04T00:17:06.000+08:00
No.0990.Satisfiability of Equality Equations
diff --git a/solution/0900-0999/0990.Satisfiability of Equality Equations/README.md b/solution/0900-0999/0990.Satisfiability of Equality Equations/README.md
@@ -63,7 +63,9 @@
 
 <!-- 这里可写通用的实现逻辑 -->
 
-并查集。
+并查集。对于本题，先遍历所有的等式，构造并查集。接着遍历所有不等式，如果不等式的两个变量处于同一个集合，说明发生矛盾，返回 false。否则遍历结束返回 true。
+
+以下是并查集的几个常用模板。
 
 模板 1——朴素并查集：
 
@@ -122,8 +124,6 @@ p[find(a)] = find(b)
 d[find(a)] = distance
 ```
 
-对于本题，先遍历所有的等式，构造并查集。接着遍历所有不等式，如果不等式的两个变量处于同一个集合，说明发生矛盾，返回 false。否则遍历结束返回 true。
-
 <!-- tabs:start -->
 
 ### **Python3**
@@ -133,20 +133,19 @@ d[find(a)] = distance
 ```python
 class Solution:
     def equationsPossible(self, equations: List[str]) -> bool:
-        p = [i for i in range(26)]
-
         def find(x):
             if p[x] != x:
                 p[x] = find(p[x])
             return p[x]
 
+        p = list(range(26))
         for e in equations:
-            a, r, b = ord(e[0]) - ord('a'), e[1:3], ord(e[3]) - ord('a')
-            if r == '==':
+            a, b = ord(e[0]) - ord('a'), ord(e[-1]) - ord('a')
+            if e[1] == '=':
                 p[find(a)] = find(b)
         for e in equations:
-            a, r, b = ord(e[0]) - ord('a'), e[1:3], ord(e[3]) - ord('a')
-            if r == '!=' and find(a) == find(b):
+            a, b = ord(e[0]) - ord('a'), ord(e[-1]) - ord('a')
+            if e[1] == '!' and find(a) == find(b):
                 return False
         return True
 ```
@@ -166,15 +165,13 @@ class Solution {
         }
         for (String e : equations) {
             int a = e.charAt(0) - 'a', b = e.charAt(3) - 'a';
-            String r = e.substring(1, 3);
-            if ("==".equals(r)) {
+            if (e.charAt(1) == '=') {
                 p[find(a)] = find(b);
             }
         }
         for (String e : equations) {
             int a = e.charAt(0) - 'a', b = e.charAt(3) - 'a';
-            String r = e.substring(1, 3);
-            if ("!=".equals(r) && find(a) == find(b)) {
+            if (e.charAt(1) == '!' && find(a) == find(b)) {
                 return false;
             }
         }
@@ -199,28 +196,22 @@ public:
 
     bool equationsPossible(vector<string>& equations) {
         p.resize(26);
-        for (int i = 0; i < 26; ++i)
-            p[i] = i;
-        for (auto e : equations)
+        for (int i = 0; i < 26; ++i) p[i] = i;
+        for (auto& e : equations)
         {
             int a = e[0] - 'a', b = e[3] - 'a';
-            char r = e[1];
-            if (r == '=')
-                p[find(a)] = find(b);
+            if (e[1] == '=') p[find(a)] = find(b);
         }
-        for (auto e : equations)
+        for (auto& e : equations)
         {
             int a = e[0] - 'a', b = e[3] - 'a';
-            char r = e[1];
-            if (r == '!' && find(a) == find(b))
-                return false;
+            if (e[1] == '!' && find(a) == find(b)) return false;
         }
         return true;
     }
 
     int find(int x) {
-        if (p[x] != x)
-            p[x] = find(p[x]);
+        if (p[x] != x) p[x] = find(p[x]);
         return p[x];
     }
 };
@@ -229,36 +220,32 @@ public:
 ### **Go**
 
 ```go
-var p []int
-
 func equationsPossible(equations []string) bool {
-	p = make([]int, 26)
+	p := make([]int, 26)
 	for i := 1; i < 26; i++ {
 		p[i] = i
 	}
+	var find func(x int) int
+	find = func(x int) int {
+		if p[x] != x {
+			p[x] = find(p[x])
+		}
+		return p[x]
+	}
 	for _, e := range equations {
 		a, b := int(e[0]-'a'), int(e[3]-'a')
-		r := e[1]
-		if r == '=' {
+		if e[1] == '=' {
 			p[find(a)] = find(b)
 		}
 	}
 	for _, e := range equations {
 		a, b := int(e[0]-'a'), int(e[3]-'a')
-		r := e[1]
-		if r == '!' && find(a) == find(b) {
+		if e[1] == '!' && find(a) == find(b) {
 			return false
 		}
 	}
 	return true
 }
-
-func find(x int) int {
-	if p[x] != x {
-		p[x] = find(p[x])
-	}
-	return p[x]
-}
 ```
 
 ### **...**
diff --git a/solution/0900-0999/0990.Satisfiability of Equality Equations/README_EN.md b/solution/0900-0999/0990.Satisfiability of Equality Equations/README_EN.md
@@ -102,27 +102,28 @@
 
 ## Solutions
 
+Union find.
+
 <!-- tabs:start -->
 
 ### **Python3**
 
 ```python
 class Solution:
     def equationsPossible(self, equations: List[str]) -> bool:
-        p = [i for i in range(26)]
-
         def find(x):
             if p[x] != x:
                 p[x] = find(p[x])
             return p[x]
 
+        p = list(range(26))
         for e in equations:
-            a, r, b = ord(e[0]) - ord('a'), e[1:3], ord(e[3]) - ord('a')
-            if r == '==':
+            a, b = ord(e[0]) - ord('a'), ord(e[-1]) - ord('a')
+            if e[1] == '=':
                 p[find(a)] = find(b)
         for e in equations:
-            a, r, b = ord(e[0]) - ord('a'), e[1:3], ord(e[3]) - ord('a')
-            if r == '!=' and find(a) == find(b):
+            a, b = ord(e[0]) - ord('a'), ord(e[-1]) - ord('a')
+            if e[1] == '!' and find(a) == find(b):
                 return False
         return True
 ```
@@ -140,15 +141,13 @@ class Solution {
         }
         for (String e : equations) {
             int a = e.charAt(0) - 'a', b = e.charAt(3) - 'a';
-            String r = e.substring(1, 3);
-            if ("==".equals(r)) {
+            if (e.charAt(1) == '=') {
                 p[find(a)] = find(b);
             }
         }
         for (String e : equations) {
             int a = e.charAt(0) - 'a', b = e.charAt(3) - 'a';
-            String r = e.substring(1, 3);
-            if ("!=".equals(r) && find(a) == find(b)) {
+            if (e.charAt(1) == '!' && find(a) == find(b)) {
                 return false;
             }
         }
@@ -173,28 +172,22 @@ public:
 
     bool equationsPossible(vector<string>& equations) {
         p.resize(26);
-        for (int i = 0; i < 26; ++i)
-            p[i] = i;
-        for (auto e : equations)
+        for (int i = 0; i < 26; ++i) p[i] = i;
+        for (auto& e : equations)
         {
             int a = e[0] - 'a', b = e[3] - 'a';
-            char r = e[1];
-            if (r == '=')
-                p[find(a)] = find(b);
+            if (e[1] == '=') p[find(a)] = find(b);
         }
-        for (auto e : equations)
+        for (auto& e : equations)
         {
             int a = e[0] - 'a', b = e[3] - 'a';
-            char r = e[1];
-            if (r == '!' && find(a) == find(b))
-                return false;
+            if (e[1] == '!' && find(a) == find(b)) return false;
         }
         return true;
     }
 
     int find(int x) {
-        if (p[x] != x)
-            p[x] = find(p[x]);
+        if (p[x] != x) p[x] = find(p[x]);
         return p[x];
     }
 };
@@ -203,36 +196,32 @@ public:
 ### **Go**
 
 ```go
-var p []int
-
 func equationsPossible(equations []string) bool {
-	p = make([]int, 26)
+	p := make([]int, 26)
 	for i := 1; i < 26; i++ {
 		p[i] = i
 	}
+	var find func(x int) int
+	find = func(x int) int {
+		if p[x] != x {
+			p[x] = find(p[x])
+		}
+		return p[x]
+	}
 	for _, e := range equations {
 		a, b := int(e[0]-'a'), int(e[3]-'a')
-		r := e[1]
-		if r == '=' {
+		if e[1] == '=' {
 			p[find(a)] = find(b)
 		}
 	}
 	for _, e := range equations {
 		a, b := int(e[0]-'a'), int(e[3]-'a')
-		r := e[1]
-		if r == '!' && find(a) == find(b) {
+		if e[1] == '!' && find(a) == find(b) {
 			return false
 		}
 	}
 	return true
 }
-
-func find(x int) int {
-	if p[x] != x {
-		p[x] = find(p[x])
-	}
-	return p[x]
-}
 ```
 
 ### **...**
diff --git a/solution/0900-0999/0990.Satisfiability of Equality Equations/Solution.cpp b/solution/0900-0999/0990.Satisfiability of Equality Equations/Solution.cpp
@@ -4,28 +4,22 @@ class Solution {
 
     bool equationsPossible(vector<string>& equations) {
         p.resize(26);
-        for (int i = 0; i < 26; ++i)
-            p[i] = i;
-        for (auto e : equations)
+        for (int i = 0; i < 26; ++i) p[i] = i;
+        for (auto& e : equations)
         {
             int a = e[0] - 'a', b = e[3] - 'a';
-            char r = e[1];
-            if (r == '=')
-                p[find(a)] = find(b);
+            if (e[1] == '=') p[find(a)] = find(b);
         }
-        for (auto e : equations)
+        for (auto& e : equations)
         {
             int a = e[0] - 'a', b = e[3] - 'a';
-            char r = e[1];
-            if (r == '!' && find(a) == find(b))
-                return false;
+            if (e[1] == '!' && find(a) == find(b)) return false;
         }
         return true;
     }
 
     int find(int x) {
-        if (p[x] != x)
-            p[x] = find(p[x]);
+        if (p[x] != x) p[x] = find(p[x]);
         return p[x];
     }
 };
diff --git a/solution/0900-0999/0990.Satisfiability of Equality Equations/Solution.go b/solution/0900-0999/0990.Satisfiability of Equality Equations/Solution.go
@@ -1,30 +1,26 @@
-var p []int
-
 func equationsPossible(equations []string) bool {
-	p = make([]int, 26)
+	p := make([]int, 26)
 	for i := 1; i < 26; i++ {
 		p[i] = i
 	}
+	var find func(x int) int
+	find = func(x int) int {
+		if p[x] != x {
+			p[x] = find(p[x])
+		}
+		return p[x]
+	}
 	for _, e := range equations {
 		a, b := int(e[0]-'a'), int(e[3]-'a')
-		r := e[1]
-		if r == '=' {
+		if e[1] == '=' {
 			p[find(a)] = find(b)
 		}
 	}
 	for _, e := range equations {
 		a, b := int(e[0]-'a'), int(e[3]-'a')
-		r := e[1]
-		if r == '!' && find(a) == find(b) {
+		if e[1] == '!' && find(a) == find(b) {
 			return false
 		}
 	}
 	return true
-}
-
-func find(x int) int {
-	if p[x] != x {
-		p[x] = find(p[x])
-	}
-	return p[x]
 }
diff --git a/solution/0900-0999/0990.Satisfiability of Equality Equations/Solution.java b/solution/0900-0999/0990.Satisfiability of Equality Equations/Solution.java
@@ -8,15 +8,13 @@ public boolean equationsPossible(String[] equations) {
         }
         for (String e : equations) {
             int a = e.charAt(0) - 'a', b = e.charAt(3) - 'a';
-            String r = e.substring(1, 3);
-            if ("==".equals(r)) {
+            if (e.charAt(1) == '=') {
                 p[find(a)] = find(b);
             }
         }
         for (String e : equations) {
             int a = e.charAt(0) - 'a', b = e.charAt(3) - 'a';
-            String r = e.substring(1, 3);
-            if ("!=".equals(r) && find(a) == find(b)) {
+            if (e.charAt(1) == '!' && find(a) == find(b)) {
                 return false;
             }
         }
diff --git a/solution/0900-0999/0990.Satisfiability of Equality Equations/Solution.py b/solution/0900-0999/0990.Satisfiability of Equality Equations/Solution.py

Original file line number	Diff line number	Diff line change
`@@ -4,28 +4,22 @@ class Solution {`
`4`	`4`
`5`	`5`	`bool equationsPossible(vector<string>& equations) {`
`6`	`6`	`p.resize(26);`
`7`		`- for (int i = 0; i < 26; ++i)`
`8`		`- p[i] = i;`
`9`		`- for (auto e : equations)`
	`7`	`+ for (int i = 0; i < 26; ++i) p[i] = i;`
	`8`	`+ for (auto& e : equations)`
`10`	`9`	`{`
`11`	`10`	`int a = e[0] - 'a', b = e[3] - 'a';`
`12`		`- char r = e[1];`
`13`		`- if (r == '=')`
`14`		`- p[find(a)] = find(b);`
	`11`	`+ if (e[1] == '=') p[find(a)] = find(b);`
`15`	`12`	`}`
`16`		`- for (auto e : equations)`
	`13`	`+ for (auto& e : equations)`
`17`	`14`	`{`
`18`	`15`	`int a = e[0] - 'a', b = e[3] - 'a';`
`19`		`- char r = e[1];`
`20`		`- if (r == '!' && find(a) == find(b))`
`21`		`- return false;`
	`16`	`+ if (e[1] == '!' && find(a) == find(b)) return false;`
`22`	`17`	`}`
`23`	`18`	`return true;`
`24`	`19`	`}`
`25`	`20`
`26`	`21`	`int find(int x) {`
`27`		`- if (p[x] != x)`
`28`		`- p[x] = find(p[x]);`
	`22`	`+ if (p[x] != x) p[x] = find(p[x]);`
`29`	`23`	`return p[x];`
`30`	`24`	`}`
`31`	`25`	`};`
Original file line number	Diff line number	Diff line change
`@@ -8,15 +8,13 @@ public boolean equationsPossible(String[] equations) {`
`8`	`8`	`}`
`9`	`9`	`for (String e : equations) {`
`10`	`10`	`int a = e.charAt(0) - 'a', b = e.charAt(3) - 'a';`
`11`		`- String r = e.substring(1, 3);`
`12`		`- if ("==".equals(r)) {`
	`11`	`+ if (e.charAt(1) == '=') {`
`13`	`12`	`p[find(a)] = find(b);`
`14`	`13`	`}`
`15`	`14`	`}`
`16`	`15`	`for (String e : equations) {`
`17`	`16`	`int a = e.charAt(0) - 'a', b = e.charAt(3) - 'a';`
`18`		`- String r = e.substring(1, 3);`
`19`		`- if ("!=".equals(r) && find(a) == find(b)) {`
	`17`	`+ if (e.charAt(1) == '!' && find(a) == find(b)) {`
`20`	`18`	`return false;`
`21`	`19`	`}`
`22`	`20`	`}`