HDU 1427 Calculator 24 points

Calculator 24 pointsTime limit:2000/1000 MS (java/others) Memory limit:65536/32768 K (java/others) Total Submission (s): 3226 Accepted Submission (s): 775

Problem Description Calculator 24 points believe that most people have played. is to give you a random four cards, including a (1), 2,3,4,5,6,7,8,9,10,j (one), Q (K), K. (13). Requires only the ' + ', '-', ' * ', '/' operators, and parentheses to change the order of operations, so that the result of the operation is finally 24 (each number must and can only be used once). The game is very easy, but it is often frustrating to encounter the situation without solution. Your task is to infer whether there is a solution for each group of randomly generated four cards. We also stipulate that no decimals can be seen in the entire calculation process.

Input data for each group in one row, given four cards.

Outputs the output of each set of input data in the corresponding row. If there is a solution, the output is "Yes" and no solution is output "no".

Sample Input

A 2 3 63 3 8 8

Sample Output

YesNo

Algorithm Analysis:

First, the whole arrangement, followed by deep search, note that there are only two cases of parentheses ([email protected]) @ ([email protected]) and (([email protected]) @c) @d.

#include <iostream> #include <algorithm>using namespace std;int res[4];void dfs (int sum, int cur, int temp);    BOOL flag = 0;int Main () {char s[3];    int i,j,k;            while (1) {for (i = 0;i < 4;i + +) {if (scanf ("%s", s) = = EOF) return 0;            if (s[0] = = ' A ') res[i] = 1;            else if (s[0] = = ' J ') res[i] = 11;            else if (s[0] = = ' Q ') res[i] = 12;            else if (s[0] = = ' K ') res[i] = 13;            else if (s[0] = = ' 1 ' && s[1] = = ' 0 ') res[i] = 10;        else res[i] = s[0]-' 0 ';        } sort (res, res+4);        Flag = 0;        Do {DFS (res[0], 1, res[1]);        }while (Next_permutation (res, res+4) &&!flag);        if (flag) printf ("yes\n");    else printf ("no\n"); } return 0;}    void Dfs (int sum, int cur, int temp) {if (flag) return;        if (cur==3) {if (sum+temp==24) flag=1;        if (sum-temp==24) flag=1;         if (sum*temp==24)   flag=1;        if (temp!=0&&sum%temp==0&&sum/temp==24) flag=1;    Return    } dfs (Sum+temp, cur+1, res[cur+1]);    DFS (Sum-temp, cur+1, res[cur+1]);    DFS (Sum*temp, cur+1, res[cur+1]);    if (temp!=0&&sum%temp==0) DFS (sum/temp, cur+1, res[cur+1]);    DFS (SUM, cur+1, temp+res[cur+1]);    DFS (SUM, cur+1, temp-res[cur+1]);    DFS (SUM, cur+1, temp*res[cur+1]); if (res[cur+1]!=0&&temp%res[cur+1]==0) DFS (sum, cur+1, temp/res[cur+1]);}

There is also a solution,

#include <stdio.h> #include <string.h>int a[10];int map[10];int flag = 1;int Get (char *str) {if (str[0] = = ' a ') r  Eturn 1;if (str[0] = = ' 1 ') return 10;if (str[0] = = ' J ') return 11;if (str[0] = = ' Q ') return 12;if (str[0] = = ' K ') return 13;return Str[0]-' 0 ';}  void DFS (int s1,int s2,int k,int x)//([email protected]) @ ([email protected]) {int i;if (k = = 4) {if (x = = 1) {if (S1 = = 24 | | S1 = = -24) {flag = 1;}} Else{if (S1 + s2 = = | | S1 + s2 = -24 | | s1-s2 = = | | s1-s2 = -24 | | S1 * s2 = | | S1 * s2 = -24) flag = 1;if ( S2 && S1% s2 = = 0 && S1/s2 = =) {flag = 1;}} return;} for (i = 1;i <= 4; i++) {if (!map[i]) {Map[i] = 1;if (k = = 0) {DFS (a[i],s2,k+1,1);} else if (k = = 1) {DFS (s1+a[i],s2,k+1,1);D FS (s1-a[i],s2,k+1,1);D FS (s1*a[i],s2,k+1,1), if (A[i] && s1% a[i] = = 0) dfs (s1/a[i],s2,k+1,1);} Else{if (k = = 2) {DFS (s1+a[i],s2,k+1,1);D FS (s1-a[i],s2,k+1,1);D FS (s1*a[i],s2,k+1,1), if (A[i] && s1% a[i] = = 0) DFS (s1/a[i],s2,k+1,1);D FS (s1,a[i],k+1,2);} Else{if (x = = 1) {DFS (s1+a[i],s2,k+1,1);D FS (s1-a[i],s2,k+1,1);D FS (s1*a[i],s2,k+1,1), if (A[i] && s1% a[i] = = 0) DFS (s1/a[i],s2,k+ );} Else{dfs (s1,s2+a[i],k+1,2);D FS (s1,s2-a[i],k+1,2);D FS (s1,s2*a[i],k+1,2), if (a[i] && s2% a[i] = = 0) DFS (s1,s2/a [i],k+1,2);}}} Map[i] = 0;}}} int main () {char str[12];int i;while (scanf ("%s", str)!=eof) {flag = 0;a[1] = get (str); for (i = 2;i <= 4;i++) {scanf ("%s", St R); A[i] = get (str);} memset (map,0,sizeof (map));D FS (0,0,0,1), if (flag) printf ("yes\n"); elseprintf ("no\n");} return 0;}

For the use of the Next_permutation function in C + + (iterative interview) and C (subscript access), the function type return value is type bool.

C++:

#include <iostream> #include <algorithm> #include <string> using namespace std; int main () {    string str;    Cin >> str;    Sort (Str.begin (), Str.end ());    cout << str << endl;    while (Next_permutation (Str.begin (), Str.end ()))    {        cout << str << endl;    }    return 0;}

C:

#include <cstdio> #include <algorithm> #include <cstring> #define MAX using namespace std; int main () {    int length;    Char Str[max];    Gets (str);    Length = strlen (str);    Sort (str, str + length);    Puts (str);    while (Next_permutation (str, str + length))    {        puts (str);    }    return 0;}

HDU 1427 Calculator 24 points