标签：des style blog http io ar color os sp
Problem I
23 Out of 5
Input: standard input
Output: standard output
Time Limit: 1 second
Memory Limit: 32 MB
Your task is to write a program that can decide whether you can find an arithmetic expression consisting of five given numbers (1<=i<=5) that will yield the value 23.
For this problem we will only consider arithmetic expressions of the following from:
where : {1,2,3,4,5} -> {1,2,3,4,5} is a bijective function
and {+,-,*} (1<=i<=4)
The Input consists of 5-Tupels of positive Integers, each between 1 and 50.
Input is terminated by a line containing five zero‘s. This line should not be processed.
For each 5-Tupel print "Possible" (without quotes) if their exists an arithmetic expression (as described above) that yields 23. Otherwise print "Impossible".
1 1 1 1 1
1 2 3 4 5
2 3 5 7 11
0 0 0 0 0
Impossible
Possible
Possible
1 #include <iostream> 2 #include <cstdio> 3 #include <cstring> 4 #include <algorithm> 5 using namespace std; 6 7 int cal(int a,char c,int b) { 8 if (c == ‘+‘) return a + b; 9 if (c == ‘-‘) return a - b; 10 if (c == ‘*‘) return a * b; 11 } 12 13 int a[5]; 14 char s[4] = {"+-*"}; 15 int dfs(int sum ,int cur) { 16 if (cur == 5) { 17 if (sum == 23) return 1; 18 else return 0; 19 } 20 for (int i = 0;i < 3;i++) { 21 if (dfs(cal(sum,s[i],a[cur]),cur + 1)) return 1; 22 } 23 return 0; 24 } 25 26 int main () { 27 // freopen("1.in","r",stdin); 28 while (cin >> a[0]) { 29 for (int i = 1;i < 5;i++) { 30 cin >> a[i]; 31 } 32 if (a[0] == 0) break; 33 int ok = 0; 34 sort(a,a + 5); 35 do { 36 if(dfs(a[0],1)) { 37 cout << "Possible" << endl; 38 ok = 1; 39 break; 40 } 41 }while (next_permutation(a,a + 5)); 42 if (ok == 0) cout << "Impossible" << endl; 43 } 44 }
标签：des style blog http io ar color os sp
原文地址：http://www.cnblogs.com/xiaoshanshan/p/4128240.html
