poj 3187

输入n,sum，求1~n的数，如何排列之后，相邻两列相加，直到得出最后的结果等于sum，

3   1   2   4

  4   3   6

    7   9

     16

枚举每种排列组合的情况，算sum，合适就退出。
算的时候别傻乎乎的去模拟，用笔算一下就会发现，每次算sum的每个系数是有规律的，是杨辉三角。

0.这道题一次过，Good！

#include <iostream>
#include <cstdio>
#include <iomanip>
#include <string>
#include <cstdlib>
#include <cstring>
#include <queue>
#include <set>
#include <vector>
#include <map>
#include <algorithm>
#include <cmath>
#include <stack>
#include <stdlib.h>
#include <stdio.h>

#define INF 0x3f3f3f3f
#define LINF 0x3f3f3f3f3f3f3f3f
#define ll long long
#define ull unsigned long long
#define uint unsigned int
#define l(x) x<<1
#define r(x) x<<1|1
#define ms(a,b) memset(a,b,sizeof(a))

using namespace std;

int yh[10][10] = {
	1,0,0,0,0,0,0,0,0,0,
	1,1,0,0,0,0,0,0,0,0,
	1,2,1,0,0,0,0,0,0,0,
	1,3,3,1,0,0,0,0,0,0,
	1,4,6,4,1,0,0,0,0,0,
	1,5,10,10,5,1,0,0,0,0,
	1,6,15,20,15,6,1,0,0,0,
	1,7,21,35,35,21,7,1,0,0,
	1,8,28,56,70,56,28,8,1,0,
	1,9,36,84,126,126,84,36,9,1,
};

int n, m,ans;
int de[11];

int main() {
	cin >> n >> m;
	for (int i = 0; i < n; i++)
		de[i] = i + 1;

	while (next_permutation(de, de + n)) {
		ans = 0;
		for (int i = 0; i < n; i++) {
			ans += yh[n - 1][i] * de[i];
		}
		if (ans == m) break;
	}

	for (int i = 0; i < n; i++) {
		cout << de[i] << " ";
	}
	cout << endl;

	return 0;
}