Update 67. 把字符串转换成整数.md

题目链接改为力扣中的对应题目，题目描述和代码按该题的接口调整。

notes/67. 把字符串转换成整数.md

@@ -2,7 +2,7 @@
 
 ## 题目链接
 
-[NowCoder](https://www.nowcoder.com/practice/1277c681251b4372bdef344468e4f26e?tpId=13&tqId=11202&tPage=1&rp=1&ru=/ta/coding-interviews&qru=/ta/coding-interviews/question-ranking&from=cyc_github)
+[Leetcode](https://leetcode.cn/problems/ba-zi-fu-chuan-zhuan-huan-cheng-zheng-shu-lcof/)
 
 ## 题目描述
 
@@ -21,19 +21,33 @@ Output:
 ## 解题思路
 
 ```java
-public int StrToInt(String str) {
+public int myAtoi(String str) {
     if (str == null || str.length() == 0)
         return 0;
-    boolean isNegative = str.charAt(0) == '-';
-    int ret = 0;
-    for (int i = 0; i < str.length(); i++) {
-        char c = str.charAt(i);
-        if (i == 0 && (c == '+' || c == '-'))  /* 符号判定 */
-            continue;
-        if (c < '0' || c > '9')                /* 非法输入 */
-            return 0;
-        ret = ret * 10 + (c - '0');
+    int i = 0, n = str.length();
+    while (i < n && str.charAt(i) == ' ') {
+        i++;
     }
-    return isNegative ? -ret : ret;
+    if (i == n)
+        return 0;
+    int sign = 1;
+    char c = str.charAt(i);
+    if (c == '+' || c == '-') {
+        sign = c == '-' ? -1 : 1;
+        i++;
+    }
+    int ret = 0;
+    int border = Integer.MAX_VALUE / 10;
+    while (i < n) {
+        c = str.charAt(i);
+        if (c < '0' || c > '9')
+            break;
+        if (ret > border || (ret == border && c > '7')) {
+            return sign == 1 ? Integer.MAX_VALUE : Integer.MIN_VALUE;
+        }
+        ret = ret * 10 + (c - '0');
+        i++;
+    }
+    return sign * ret;
 }
 ```