求帮助

$WAcode(50pts):$

#include<bits/stdc++.h>
using namespace std;
double x;
bool a[2100000];
int n,t,idx;
int main(){
	scanf("%d",&n);
	while(n--){
		scanf("%lf%d",&x,&t);
		for(int i=1;i<=t;i++){
			int value=floor(x*i);
			a[value]=!a[value];
			if(a[value])idx=value;
		}
	}
	printf("%d",idx);
	return 0;
}