Add Solution2.java to problems 63

Author: huaxu1024

solution/0063.Unique Paths II/Solution2.java

@@ -0,0 +1,42 @@
+class Solution {
+    public int uniquePathsWithObstacles(int[][] dp) {
+        if (dp[0][0] == 1 || dp[dp.length - 1][dp[0].length - 1] == 1) return 0;
+        for (int i = 1; i < dp.length; i ++) {
+            if (dp[i][0] == 1) {
+                dp[i][0] = -1;
+                continue;
+            }
+            if (dp[i - 1][0] == -1) {
+                dp[i][0] = -1;
+            } else dp[i][0] = 1;
+        }
+        for (int i = 1; i < dp[0].length; i ++) {
+            if (dp[0][i] == 1) {
+                dp[0][i] = -1;
+                continue;
+            }
+            if (dp[0][i - 1] == -1) {
+                dp[0][i] = -1;
+            } else dp[0][i] = 1;
+        }
+        for (int i = 1; i < dp.length; i ++) {
+            for (int j = 1; j < dp[0].length; j ++) {
+                if (dp[i][j] == 1) {
+                    dp[i][j] = -1;
+                } else if (dp[i][j - 1] == -1 && dp[i - 1][j] == -1) {
+                    dp[i][j] = -1;
+                } else if (dp[i][j - 1] == -1) {
+                    dp[i][j] = dp[i - 1][j];
+                } else if (dp[i - 1][j] == -1) {
+                    dp[i][j] = dp[i][j - 1];
+                } else {
+                    dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
+                }
+            }
+        }
+        int res = dp[dp.length - 1][dp[0].length - 1];
+        if (res == 0) return 1;
+        if (res == -1) return 0;
+        return res;
+    }
+}