1.题目描述：点击打开链接
2.解题思路：比赛时没有想到好的思路，后来才发现，只需要t串中的字符是s串中出现次数最多的字符即可，根据乘法原理可知：最终结果是pow(num,n)，其中num是s串中次数最多的字符的个数。
3.代码：
#define _CRT_SECURE_NO_WARNINGS #include<iostream>#include<algorithm>#include<string>#include<sstream>#include<set>#include<vector>#include<stack>#include<map>#include<queue>#include<deque>#include<cstdlib>#include<cstdio>#include<cstring>#include<cmath>#include<ctime>#include<functional>using namespace std;int n;const int MOD = 1000000000 + 7;string s;int vis[4];char*cg = "ACGT";int id(char c){ return strchr(cg, c) – cg; }int P(int e, int n){if (n == 0)return 1;int x = P(e, n / 2);long long ans = (long long)x*x%MOD;if (n & 1)ans = ans*e%MOD;return (int)ans;}int main(){//freopen("test.txt", "r", stdin);while (cin >> n){cin >> s;int cnt = 0;int num = 0;int len = s.length();memset(vis, 0, sizeof(vis));for (int i = 0; i < len; i++){vis[id(s[i])]++;cnt = max(cnt, vis[id(s[i])]);}for (int i = 0; i < 4;i++)if (vis[i] == cnt)num++;cout << P(num, n) << endl;}return 0;}
，想念我的时候，不要忘记我也在想念你。
