init commit

archive/algorithm/leetcode/22.c

@@ -0,0 +1,48 @@
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+void dfs(char** ret, int* num, char* S, int n, int use, int ruse) {
+    if (use >= n && ruse >= n) {
+        //左括号用完了
+        ret[*num] = S;
+        *num += 1;
+        return;
+    }
+    if (use < n) {
+        char* tmp = malloc((n * 2) + 1);
+        memset(tmp, 0, (n * 2) + 1);
+        strcpy(tmp, S);
+        tmp[strlen(S)] = '(';
+        dfs(ret, num, tmp, n, use + 1, ruse);
+    }
+    if (ruse < use) {
+        char* tmp = malloc((n * 2) + 1);
+        memset(tmp, 0, (n * 2) + 1);
+        strcpy(tmp, S);
+        S[strlen(S)] = ')';
+        dfs(ret, num, S, n, use, ruse + 1);
+    }
+}
+
+/**
+ * Note: The returned array must be malloced, assume caller calls free().
+ */
+char** generateParenthesis(int n, int* returnSize) {
+    char** ret = malloc(pow(n, n) * sizeof(char*));
+    char* S = malloc((n * 2) + 1);
+    memset(S, 0, (n * 2) + 1);
+    dfs(ret, returnSize, S, n, 0, 0);
+    return ret;
+}
+// 1 2 5 14 42 132
+int main() {
+    int num = 0;
+    char** ret = generateParenthesis(10, &num);
+    for (int i = 0; i < num; i++) {
+        printf("%s\n", ret[i]);
+    }
+    getchar();
+    return 0;
+}