Solve Problem 946 - Validate Stack Sequence

Author: hieu

src/contest/ReadMe.java

@@ -11,8 +11,8 @@ public class ReadMe {
     // backtrack:           1307[!]     1239[v]     1219[v]     1291[~]     1286[v]
     // dp:                  1349[!]     1340[v]     1367[v]     1388[!]     1406[!]
     // divide & conquer:    932[!]      514         903[v]      327[x]      315[!]
-    // greedy:              1354[!]     1353[x]     1338[v]     1383[!]     1403
-    // stack:               1190[!]     975[x]      1381[v]     901[v]      946
+    // greedy:              1354[!]     1353[x]     1338[v]     1383[!]     1403[v]
+    // stack:               1190[!]     975[x]      1381[v]     901[v]      946[v]
     // binary search:       1351[v]     1337[v]     1292[!]     1235[!]     1237
     // 2 pointers:          1248[*]     1234[v]     986[v]      826[x]      977
     // sliding window:      1208[v]     1040[!]     995[!]      567[v]      978[v]

src/stack/Problem946_ValidateStackSequences.java

@@ -0,0 +1,16 @@
+package stack;
+
+public class Problem946_ValidateStackSequences {
+
+    public boolean validateStackSequences(int[] pushed, int[] popped) {
+        int i = -1, j = 0;
+        for (int x : pushed) {
+            pushed[++i] = x;
+            while (i >= 0 && pushed[i] == popped[j]) {
+                j++;
+                i--;
+            }
+        }
+        return j == popped.length;
+    }
+}