添加 最大子序和(动态规划).md c语言版本

problems/0053.最大子序和（动态规划）.md

@@ -239,6 +239,35 @@ function maxSubArray(nums: number[]): number {
     return resMax
 }
 ```
+### C:
+```c
+bool isSubsequence(char *s, char *t)
+{
+    bool **dp = malloc(sizeof(bool *) * (strlen(s) + 1));
+    for (int i = 0; i <= strlen(s); i++)
+    {
+        dp[i] = malloc(sizeof(bool) * (strlen(t) + 1));
+    }
+    // 初始化
+    for (int i = 0; i <= strlen(s); i++)
+    {
+        dp[i][0] = false;
+    }
+    for (int j = 0; j <= strlen(t); j++)
+    {
+        dp[0][j] = true;
+    }
+    // 遍历
+    for (int i = 1; i <= strlen(s); i++)
+    {
+        for (int j = 1; j <= strlen(t); j++)
+        {
+            dp[i][j] = s[i - 1] == t[j - 1] ? dp[i - 1][j - 1] : dp[i][j - 1];
+        }
+    }
+    return dp[strlen(s)][strlen(t)];
+}
+```
 
 
 

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;
+}
+```
 
 

problems/0435.无重叠区间.md

@@ -440,7 +440,7 @@ impl Solution {
 }
 ```
 ### C
-
+- 按右边界排序
 ```c
 // 按照区间右边界排序
 int cmp(const void * var1, const void * var2){
@@ -465,6 +465,41 @@ int eraseOverlapIntervals(int** intervals, int intervalsSize, int* intervalsColS
     return intervalsSize - count;
 }
 ```
+- 按左边界排序
+```c
+// 按照区间左边界排序
+int cmp(const void *a, const void *b)
+{
+    return *((int **)a)[0] - *((int **)b)[0];
+}
+int eraseOverlapIntervals(int **intervals, int intervalsSize, int *intervalsColSize)
+{
+    if (intervalsSize == 0)
+    {
+        return 0;
+    }
+    qsort(intervals, intervalsSize, sizeof(intervals[0]), cmp);
+    // count: 重叠的区间数量
+    int count = 0;
+    // end: 区间分割点
+    int end = intervals[0][1];
+    for (int i = 1; i < intervalsSize; i++)
+    {
+        if (intervals[i][0] < end)
+        {
+            // 说明有重合, end取2个区间中较小的右边界
+            end = fmin(end, intervals[i][1]);
+            count++;
+        }
+        else
+        {
+            // 没有重合，更新end
+            end = intervals[i][1];
+        }
+    }
+    return count;
+}
+```