Cent saving

input/code.cpp: In function 'int main()':
input/code.cpp:26:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i = 0; i < vi.size(); ++i){
                              ^

#include <bits/stdc++.h>
#define _ ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0), cout.precision(6);

using namespace std;

int main(){ _
	int TC;	cin >> TC;
	while(TC--){
		int n,sum = 0;	cin >> n;
		vector<int> vi(n, 0);
		for(int i = 0; i < n; ++i){
			cin >> vi[i];
			sum += vi[i];
			vi[i] %= 5;
			switch(vi[i]){
				case 0:	vi[i] = 0;	break;
				case 1:	vi[i] = -1;	break;
				case 2:	vi[i] = -2;	break;
				case 3:	vi[i] = 2;	break;
				case 4:	vi[i] = 1;	break;
			}
		}

		sort(vi.begin(), vi.end());
		int save = 0, temp = 0;
		for(int i = 0; i < vi.size(); ++i){
			if(vi[i] <= 0){
				if(temp > 0){	save += temp;	temp = 0;}
				save += vi[i];
			}else{
				temp += vi[i];
				switch(temp){
					case 2:	temp = 2;	break;	
					case 3:	temp = -2;	break;
					case 4:	temp = -1;	break;
				}
				if(temp < 0){
					save += temp;
					temp = 0;
				}
			}
		}

		cout << sum + save << endl;
	}
	return 0;
}

Test 1

Verdict: WRONG ANSWER

Test 2

Verdict: WRONG ANSWER