第七届蓝桥杯省赛第六题方格填数（next_permutation）

填入0~9的数字。要求：连续的两个数字不能相邻。
（左右、上下、对角都算相邻）
一共有多少种可能填写的方案？
请填写表示方案数目的整数～

分析：从左到右从上到下标为0～9，将a[10]中的数字依次填入，所以只要将a数组从0123456789一直全排列试到9876543210，测试每一个结果是否满足，满足条件的次数累加得到的就是方案数目～答案是1580～

#include <iostream>
#include <algorithm>
using namespace std;
int a[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
bool judge(int i, int j) {
    return (a[i] - a[j] == 1 || a[i] - a[j] == -1);
}
bool func() {
    if (judge(0, 1) || judge(0, 3) ||judge(0, 4) ||judge(0, 5) ||judge(1, 2)||judge(1, 4) ||judge(1, 5) ||judge(1,6) ||judge(2, 5) ||judge(2, 6) ||judge(3, 4) ||judge(3, 7) ||judge(3, 8) ||  judge(4, 5) ||judge(4, 7) || judge(4, 8) ||judge(4, 9) ||judge(5, 6) ||judge(5, 8) || judge(5, 9) || judge(6, 9)|| judge(7, 8) ||judge(8, 9))
        return false;
    return true;
}
int main() {
    int n = 1, cnt = 0;
    for (int i = 1; i <= 10; i++)
        n = n * i;
    for (int i = 1; i < n; i++) {
        next_permutation(a, a+10);
        if (func() == true)
            cnt++;
    }
    cout << cnt;
    return 0;
}

#include <iostream>

#include <algorithm>

using namespace std;

int a[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};

bool judge(int i, int j) {

return (a[i] - a[j] == 1 || a[i] - a[j] == -1);

}

bool func() {

if (judge(0, 1) || judge(0, 3) ||judge(0, 4) ||judge(0, 5) ||judge(1, 2)||judge(1, 4) ||judge(1, 5) ||judge(1,6) ||judge(2, 5) ||judge(2, 6) ||judge(3, 4) ||judge(3, 7) ||judge(3, 8) || judge(4, 5) ||judge(4, 7) || judge(4, 8) ||judge(4, 9) ||judge(5, 6) ||judge(5, 8) || judge(5, 9) || judge(6, 9)|| judge(7, 8) ||judge(8, 9))

return false;

return true;

}

int main() {

int n = 1, cnt = 0;

for (int i = 1; i <= 10; i++)

n = n * i;

for (int i = 1; i < n; i++) {

next_permutation(a, a+10);

if (func() == true)

cnt++;

}

cout << cnt;

return 0;

}

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