其实本质就是时钟循环

#include<iostream>
#pragma warning(disable:4996)//忽略scanf不安全的警告
using namespace std;
unsigned long long r,y,g,st=0,t,n;//st=sum time 总时间 t为坐标轴映射时间
int traffic_signal_waiting_time(unsigned long long time, int signal){//r1 y2 g3  r->g->y
    switch(signal){
        case 1://红灯
        t=r-time;break;//将time转换到坐标轴上映射 |____红r____|_____绿g_____|_____黄y_____|
        case 2://黄灯
        t=(r+y+g)-time;break;
        case 3://绿灯
        t=r+g-time;break;
    }
    t=(t+st)%(r+y+g);//和已经走过的时间做时钟运算
    if(t<=r) return r-t;
    else if(t<g+r) return 0;
    else if(t<(r+y+g)) return (r+y+g)-t+r;
}
int main() {
    scanf("%llu %llu %llu %llu", &r, &y, &g, &n);
    unsigned long long b;int a;//a:信号灯标志 b:时间
    for(int i=0;i<n;i++){ 
        scanf("%d %llu",&a,&b);
        if(a==0) st+=b;//走路
        else st+=traffic_signal_waiting_time(b,a);//计算等待时间
    }
    cout<<st;
    return 0;
}