Reversals

#include <bits/stdc++.h>
using namespace std;

void rev(string& str, int a, int b) {
	int swaps = (int)floor((b-a+1)/2);
	for(int i = 0; i < swaps; i++) {
		swap(str[a+i], str[b-i]);
	}
}

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  string s;
  int n, m;
  cin >> n;
  cin >> m;
  cin >> s;

  for(int i = 0; i < m; i++) {
    int a, b;
    cin >> a;
		cin >> b;
		a--;
		b--;
		rev(s, a, b);
  }
  cout << s << endl;
  return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: TIME LIMIT EXCEEDED