http://acm.hdu.edu.cn/showproblem.php?pid=1427

#include <bits/stdc++.h>

using namespace std;

double epx = 1e-10;
int cmp = 24;

bool judge(vector<int> &nums) {
if (nums.size() == 1) {
if (nums[0] == cmp) return true;
return false;
}

for (int i = 0; i < nums.size(); ++i) {
for (int j = i + 1; j < nums.size(); ++j) {
vector<int> t;
for (int k = 0; k < nums.size(); ++k) {
if (k != j && k != i) t.push_back(nums[k]);
}
int a = nums[i], b = nums[j];
t.push_back(a - b);
if (judge(t)) return true;
t.pop_back();

t.push_back(b - a);
if (judge(t)) return true;
t.pop_back();

t.push_back(b * a);
if (judge(t)) return true;
t.pop_back();

t.push_back(b + a);
if (judge(t)) return true;
t.pop_back();

if (a != 0 && b % a == 0) {
t.push_back(b / a);
if (judge(t)) return true;
t.pop_back();
}

if (b != 0 && a % b == 0) {
t.push_back(a / b);
if (judge(t)) return true;
t.pop_back();
}
}
}
return false;
}
char a[22][22];
int char2double(char ch) {
if (ch == 'A') return 1;
else if (ch == 'J') return 11;
else if (ch == 'Q') return 12;
else if (ch == 'K') return 13;
else if (ch == '1') {
return 10;
} else return ch - '0';
}
void work() {
vector<int> vc;
for (int i = 0; i < 4; ++i) {
vc.push_back(char2double(a[i][0]));
}
if (judge(vc)) {
printf("Yes\n");
} else printf("No\n");
}

int main() {
// freopen("data.txt", "r", stdin);
while (scanf("%s%s%s%s", a[0], a[1], a[2], a[3]) > 0) work();
return 0;
}
View Code

#include <bits/stdc++.h>

using namespace std;

double epx = 1e-5;
double cmp = 24.0;

bool judge(vector<double>& nums) {
if (nums.size() == 1) {
if (fabs(cmp - nums[0]) < epx) return true;
return false;
}

for (int i = 0; i < nums.size(); ++i) {
for (int j = i + 1; j < nums.size(); ++j) {
vector<double> t;
for (int k = 0; k < nums.size(); ++k) {
if (k != j && k != i) t.push_back(nums[k]);
}
double a = nums[i], b = nums[j];
t.push_back(a - b);
if (judge(t)) return true;
t.pop_back();

t.push_back(b - a);
if (judge(t)) return true;
t.pop_back();

t.push_back(b * a);
if (judge(t)) return true;
t.pop_back();

t.push_back(b + a);
if (judge(t)) return true;
t.pop_back();

if (fabs(a - 0) > 10 * epx) {
t.push_back(b / a);
if (judge(t)) return true;
t.pop_back();
}

if (fabs(b - 0) > 10 * epx) {
t.push_back(a / b);
if (judge(t)) return true;
t.pop_back();
}
}
}
return false;
}

void work() {
double a, b, c, d;
cin >> a >> b >> c >> d;

vector<double> vc;
vc.push_back(a);
vc.push_back(b);
vc.push_back(c);
vc.push_back(d);
if (judge(vc)) cout << "true" << endl;
else cout << "false" << endl;
}

int main() {
work();
return 0;
}
wa

https://www.nowcoder.com/questionTerminal/fbc417f314f745b1978fc751a54ac8cb