60 lines
1.5 KiB
C++
60 lines
1.5 KiB
C++
#include<stdio.h>
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#include<string.h>
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#include<queue>
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#include<algorithm>
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using namespace std;
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int x,y;
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int main()
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{
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while(~scanf("%d%d",&x,&y))
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{
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if(y<x) printf("-1\n");
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else if(x==1) printf("%d\n",y-1);
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else
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{
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if(x==2)
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printf("%d\n",(y+1)/2);
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else if(x==3)
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{
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int a[3]={2,3,4};
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printf("%d\n",(y-3)/3+a[(y-3)%3]);
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}
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else if(x==4)
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{
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int a[4]={3,4,4,5};
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printf("%d\n",(y-4)/4+a[(y-4)%4]);
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}
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else if(x==5)
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{
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int a[5]={4,5,5,6,6};
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printf("%d\n",(y-5)/5+a[(y-5)%5]);
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}
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else if(x==6)
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{
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int a[]={5,6,6,6,7,7};
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printf("%d\n",(y-6)/6+a[(y-6)%6]);
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}
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else if(x==7)
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{
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int a[7]={6,7,7,7,8,8,9};
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printf("%d\n",(y-7)/7+a[(y-7)%7]);
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}
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else if(x==8)
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{
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int a[8]={7,8,8,9,8,9,9,10};
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printf("%d\n",(y-8)/8+a[(y-8)%8]);
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}
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else if(x==9)
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{
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int a[9]={8,9,9,9,9,10,10,10,11};
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printf("%d\n",(y-9)/9+a[(y-9)%9]);
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}
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else if(x==10)
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{
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int a[10]={9,10,10,10,11,10,11,11,11,12};
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printf("%d\n",(y-10)/10+a[(y-10)%10]);
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}
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}
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}
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}
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