有没有大佬可以帮忙看一下这段代码有啥问题吗

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

long long n, tn, cnt, nL[100010];

int main() {
	cin >> n;
	for (int i = 0; i < n; i ++) {
		cin >> tn;
		cnt += tn / 2;
		nL[i] = tn % 2;
	}
	for (int i = 0; i < n - 1; i ++) {
		if (nL[i] == 1 and nL[i + 1] == 1) {
			cnt += 1;
			nL[i] --;
			nL[i + 1]--;
		}
	}
	cout << cnt;
	return 0;
}