2272. 最大波动的子字符串

2272. 最大波动的子字符串

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题目链接：2272. 最大波动的子字符串

代码如下：

//参考链接：https://leetcode.cn/problems/substring-with-largest-variance/solutions/1494890/by-endlesscheng-5775
class Solution {
public:
	int largestVariance(string s) {
		int res = 0;
		for (char a = 'a';a <= 'z';a++) {
			for (char b = 'a';b <= 'z';b++) {
				if (b == a) {
					continue;
				}
				int f0 = 0, f1 = INT_MIN;
				for (char ch : s) {
					if (ch == a) {
						f0 = max(f0, 0) + 1;
						f1++;
					}
					else if (ch == b) {
						f1 = f0 = max(f0, 0) - 1;
					}// else f0 = max(f0, 0); 可以留到 ch 等于 a 或者 b 的时候计算，f1 不变
					res = max(res, f1);
				}
			}
		}
		return res;
	}
};