hdu 5308 I Wanna Become A 24-Point Master
题目链接：
http://acm.hdu.edu.cn/showproblem.php?pid=5308
解题思路：
尽可能的凑成24，多余的用(n-n)*n*n*·····*n=0消掉
AC代码：
#include <iostream>
#include <cstdio>
using namespace std;
int main(){
int i,n;
while(~scanf("%d",&n)){
if(n <= 3)
printf("-1\n");
else if(n == 4){
printf("1 * 2\n");// 5 n*n
printf("5 + 3\n");// 6 5*n
printf("6 + 4\n");// 7 6*n
}
else if(n == 5){
printf("1 / 2\n");// 6 1
printf("6 / 3\n");// 7 1/5
printf("4 - 7\n");// 8 24/5
printf("5 * 8\n");// 9 24
}
else if(n == 6){
printf("1 + 2\n");
printf("7 + 3\n");
printf("8 + 4\n");
printf("9 + 5\n");
printf("10 - 6\n");
}
else if(n == 7){
printf("1 / 2\n");// 8 1
printf("3 * 4\n");// 9 n*n
printf("9 - 8\n");// 10 48
printf("5 + 6\n");// 11 2*n
printf("10 / 11\n");// 12 48/14
printf("12 * 7\n");// 13 24
}
else if(n == 8){
printf("1 - 2\n");// 9 0
printf("9 * 3\n");// 10 0
printf("10 * 4\n");// 11 0
printf("11 * 5\n");// 12 0
printf("12 + 6\n");// 13 n
printf("13 + 7\n");// 14 2*n
printf("14 + 8\n");// 15 3*n
}
else if(n == 9){
printf("1 / 2\n");// 10 1
printf("3 / 4\n");// 11 1
printf("5 / 6\n");// 12 1
printf("7 + 8\n");// 13 2*n
printf("13 + 9\n");// 14 3*n
printf("14 - 10\n");// 15 26
printf("15 - 11\n");// 16 25
printf("16 - 12\n");// 17 24
}
else if(n == 10){
printf("1 / 2\n");// 11 1
printf("3 / 4\n");// 12 1
printf("5 / 6\n");// 13 1
printf("7 / 8\n");// 14 1
printf("9 + 10\n");// 15 2*n
printf("11 + 12\n");// 16 2
printf("16 + 13\n");// 17 3
printf("17 + 14\n");// 18 4
printf("18 + 15\n");// 19 24
}
else if(n == 11){
printf("1 + 2\n");// 12 2*n
printf("3 / 4\n");// 13 1
printf("5 / 6\n");// 14 1
printf("12 + 13\n");// 15 23
printf("15 + 14\n");// 16 24
printf("7 - 8\n");// 17 0
for(int i = 9; i < 12; i++)
printf("%d * %d\n",i,i+8);
printf("16 + 20\n");
}
else if(n == 12){
printf("1 + 2\n");// 13 24
printf("3 - 4\n");// 14 0
for(i = 5; i < 13; i++)
printf("%d * %d\n",i,i+9);
printf("13 + 22\n");
}
else if(n == 13){
printf("1 + 2\n");// 14 26
printf("14 / 3\n");// 15 2
printf("4 / 5\n");// 16 1
printf("6 - 16\n");// 17 12
printf("15 * 17\n");// 18 24
printf("7 - 8\n");// 19 0
for(i = 9; i < 14; i++)
printf("%d * %d\n",i,i+10);
printf("18 + 24\n");
}
else if(n == 14){
printf("1 / 2\n");// 15 1
printf("3 / 4\n");// 16 1
printf("5 - 15\n");// 17 13
printf("17 - 16\n");// 18 12
printf("6 + 7\n");// 19 28
printf("19 / 8\n");// 20 2
printf("20 * 18\n");// 21 24
printf("9 - 10\n");// 22 0
for(i = 11; i < 15; i++)
printf("%d * %d\n",i,i+11);
printf("21 + 26\n");
}
else{
printf("1 + 2\n");// n+1 2*n
printf("3 + 4\n");// n+2 2*n
printf("5 + 6\n");// n+3 2*n
printf("7 + 8\n");// n+4 2*n
printf("%d + 9\n",n+1);// n+5 3*n
printf("%d / 10\n",n+2);// n+6 2
printf("%d / 11\n",n+3);// n+7 2
printf("%d / 12\n",n+4);// n+8 2
printf("%d / 13\n",n+5);// n+9 3
printf("%d * %d\n",n+6,n+7);// n+10 4
printf("%d * %d\n",n+8,n+9);// n+11 8
printf("%d * %d\n",n+10,n+11);// n+12 24
printf("14 - 15\n");
int now = n+13;
for(i = 16; i <= n; i++,now++)
printf("%d * %d\n",i,now);
printf("%d + %d\n",n+12,now);
}
}
return 0;
}