func_code_string: #include <bits/stdc++.h>   using namespace std;   int n;   double sv[500050];   struct info {     int x, v;   } A[500050];   int main() {     scanf( %d , &n);     int l = 0;     for (int i = 0; i < n; i++) scanf( %d %d , &A[i].x, &A[i].v);     int st = n, nd = -1;     for (int i = 0; i < n; i++)       if (A[i].v > 0) {         st = i;         break;       }     for (int i = n - 1; i >= 0; i--)       if (A[i].v < 0) {         nd = i;         break;       }     if (st > nd)       puts( -1.000000000000 );     else {       int it = 100;       double low = 0, high = 1e20, mid;       while (it--) {         mid = (low + high) / 2;         double mx = -1e20, mn = 1e20;         int i;         for (i = 0; i < n; i++)           if (A[i].v > 0) sv[i] = mx = max(mx, A[i].v * mid + A[i].x);         for (i = n - 1; i >= 0; i--) {           if (A[i].v < 0)             mn = min(mn, A[i].v * mid + A[i].x);           else if (sv[i] > mn)             break;         }         if (i >= 0)           high = mid;         else           low = mid;       }       printf( %.12lf n , mid);     }     return 0;   }   