fix: 0053.最大子序和原typescript过不了leetcode，更新代码逻辑

problems/0053.最大子序和（动态规划）.md

@@ -226,18 +226,20 @@ object Solution {
 
 ```typescript
 function maxSubArray(nums: number[]): number {
-    /**
-        dp[i]：以nums[i]结尾的最大和
-     */
-    const dp: number[] = []
-    dp[0] = nums[0];
-    let resMax: number = 0;
-    for (let i = 1; i < nums.length; i++) {
-        dp[i] = Math.max(dp[i - 1] + nums[i], nums[i]);
-        resMax = Math.max(resMax, dp[i]);
+    const len = nums.length
+    if (len === 1) return nums[0]
+
+    const dp: number[] = new Array(len)
+    let resMax: number = dp[0] = nums[0]
+
+    for (let i = 1; i < len; i++) {
+        dp[i] = Math.max(dp[i - 1] + nums[i], nums[i])
+        // 注意值为负数的情况
+        if (dp[i] > resMax) resMax = dp[i]
     }
-    return resMax;
-};
+
+    return resMax
+}
 ```