题解 | #十字斩-研发#

递归

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

struct node
{
    int t,id,w;
}a[100005];

int k;
int sum[100005];
int temp;
int dfs(int l)
{
    int r = l+1;
    while(a[l].id != a[r].id)
    {
        sum[l] += dfs(r);
        r = temp;
    }
    sum[l] = (a[r].t - a[l].t) - sum[l];
    temp = r+1;
    return a[r].t - a[l].t;
}
int main()
{
    int t,n;
    cin >> t;
    while(t--)
    {
        cin >> n;
        for(int i = 1; i <= n; i++)
        {
            cin >> a[i].t >> a[i].id >> a[i].w;
        }
        dfs(0);
        int maxn = 0;
        int id = 0;
        for(int i = 1; i <= n; i++)
        {
            if(maxn < sum[i])
            {
                maxn = sum[i];
                id = a[i].id;
            }
            else if(maxn == sum[i] && id > a[i].id)
            {
                id = a[i].id;
            }
            sum[i] = 0;
            a[i].id = 0;//不清零会发生段错误 
        }
        sum[0] = 0;
        sum[n+1] = 0;
        cout << id << "\n";
    }
}