蓝桥杯 ALGO-87 算法训练 字串统计

#include <iostream>
#include <string>
#include <vector>
using namespace std;
int main() {
int num;
cin >> num;
string a;
cin >> a;
vector<string> v;
int len = a.length();
for (int i = num; i <= len; i++) {
for (int j = 0; j <= len - i; j++) {
v.push_back(a.substr(j, i));
}
}

int max = 0;
int k = 0;
vector<int> book(v.size());
for (int i = 0; i <= v.size() - 1; i++) {
for (int j = 0; j <= v.size() - 1; j++) {
if (i != j && v[i] == v[j])
book[i]++;
}
}

for (int i = 0; i <= v.size() - 1; i++) {
if (book[i] > max || (book[i] == max && v[k].length() < v[i].length())) {
k = i;
max = book[i];
}
}
cout << v[k];
return 0;
}