添加0115.不同的子序列.md C语言版本

Author: Frank-whw

problems/0115.不同的子序列.md

@@ -371,6 +371,45 @@ impl Solution {
     }
 }
 ```
+### C:
+```c
+#define MOD 1000000007
+int numDistinct(char *s, char *t)
+{
+    //dp[i][j]: t前i个字符，s前j个字符，s子序列中t出现的个数
+    int **dp = malloc(sizeof(int *) * (strlen(t) + 1));
+    for (int i = 0; i <= strlen(t); i++)
+    {
+        dp[i] = malloc(sizeof(int) * (strlen(s) + 1));
+    }
+
+    // 初始化
+    for (int i = 0; i <= strlen(t); i++)
+    {
+        dp[i][0] = 0;
+    }
+    for (int j = 0; j <= strlen(s); j++)
+    {
+        dp[0][j] = 1;
+    }
 
+    // 遍历
+    for (int i = 1; i <= strlen(t); i++)
+    {
+        for (int j = 1; j <= strlen(s); j++)
+        {
+            if (s[j - 1] == t[i - 1])
+            {
+                dp[i][j] = dp[i - 1][j - 1] + dp[i][j - 1];
+            }
+            else
+            {
+                dp[i][j] = dp[i][j - 1];
+            }
+        }
+    }
+    return dp[strlen(t)][strlen(s)] % MOD;
+}
+```