UVa 1648 (push formula) business Center

Test instructions

There's a strange elevator that can only walk up the U-floor or down D-floors at a time.

Now there are M elevators, the minimum number of floors (which must be positive) to arrive at exactly N times, and the first default is on the No. 0 floor.

Analysis:

Assuming that the elevator goes up x times, then go down n-x times, then reach the floor is Xu-(n-x) d≥0

(u+d) The minimum value for the x≥nd,x is

In other words, if nd% (u+d) = = 0, x = nd/(u+d)

otherwise x = nd/(u+d) + 1

Considering that the condition cannot be reached on the 0 floor: when nd% (u+d) = = 0 This happens, you can only have one more time on the U-level, less the next D-floor, so this will eventually stop at the U+D layer

1#include <cstdio>2 3 intMain ()4 {5     intN, M;6 7      while(SCANF ("%d%d", &n, &m) = =2)8     {9         intAns =1000000000;Ten          while(m--) One         { A             intu, D; -scanf"%d%d", &u, &d); -             if((n*d)% (u+d) = =0) {if(U+d < ans) ans = u+D;} the             Else -             { -                 intx = (n*d)/(U+D) +1; -                 intt = x* (u+d)-n*D; +                 if(T < ans) ans =T; -             } +         } Aprintf"%d\n", ans); at     } -  -     return 0; -}

code June

UVa 1648 (push formula) business Center