#include<iostream>
#include<cmath>
using namespace std;
int a[100010][3];
int main()
{
    int i=1,j=1,k,expect,down,max,temp,cha,xl,num,s,price,p;
    cin>>expect;
    while(cin>>a[i][1]>>a[i][2]&&a[i][1]!=-1&&a[i] [2]!=-1)
    {
	    i++;
	    if(i>2&&a[i-1][1]-a[i-2][1]>1)
	    {
		    i--;
		    cha=(a[i-1][2]-a[i][2])/(a[i][1]-a[i-1][1]);
		    temp=a[i][1];
		    for(j=a[i-1][1]+1;j<=temp;j++)
		    {
		    	a[i][1]=j;
		    	a[i][2]=a[i-1][2]-cha;
		    	i++;
		    }
	    }
    }
    cin>>down;
    i--;
    xl=a[i][2];
    while(xl>0)
    {
	    if(xl-down<0)break;
	    else
	    {
	    	xl-=down;
	    	i++;
	    	a[i][1]=a[i-1][1]+1;
	    	a[i][2]=xl;
	    }
    }
    for(j=1;j<=10000;j++)
    {
	    max=-99999;
	    for(k=1;k<=i;k++)
	    {
		    num=(a[k][1]-a[1][1]+j)*a[k][2];
		    if(num>=max)
		    {
		        max=num;
					price=a[k][1];
			     p=1;
		    }
	    }
	    if(price==expect){cout<<j*p;return 0;}
	    max=-99999;
	    for(k=1;k<=i;k++)
	    {
		    num=(a[k][1]-a[1][1]-j)*a[k][2];
		    if(num>=max)
		    {
		       max=num;
			    price=a[k][1];	
			    p=-1;
		    }
	    }
	    if(price==expect){cout<<j*p;return 0;}
    }
}

我未输出“NO SOLUTION”但AC了