String Deletion

链接：https://vjudge.net/contest/400848#problem/D
注：a/2向上取整就是(a+1)/2
代码：

#include<bits/stdc++.h>
using namespace std;
const int maxn = 2e5+7;
char s[maxn];
int a[maxn];
int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        int n;
        scanf("%d",&n);
        scanf("%s", s+1);
        int now = 1, tot = 0;
        for(int i = 2; i <= n; i++) {
            if(s[i] == s[i-1]) {
                now++;
            }
            else{
                a[++tot] = now;
                now = 1;
            }
        }
        a[++tot] = now;
        int ans = 0;
        for(int i = 1; i <= tot; i++) {
            if(a[i] > 1) {
                ans++;
            }
            else {
                bool flag = 0;
                for(int j = i + 1; j <= tot; j++) {
                    if(a[j] > 1) {
                        a[j]--;
                        ans++;
                        flag = 1;
                        break;
                    }
                }
                if(!flag) {
                    ans += (tot-i+2)/2;
                    break;
                }
            }
        }
        cout << ans << endl;
    }
    return 0;
}