【BZOJ】1653: [Usaco2006 Feb]Backward Digit Sums（暴力）

最新推荐文章于 2025-12-10 11:19:03 发布

转载最新推荐文章于 2025-12-10 11:19:03 发布 · 126 阅读

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本文探讨了一款复杂游戏的解决策略，通过使用特定算法和排序方法来确定初始序列，帮助玩家理解并掌握游戏规则。文章详细介绍了游戏流程、算法实现及优化策略，旨在提升玩家的游戏体验。

http://www.lydsy.com/JudgeOnline/problem.php?id=1653

看了题解才会的。。T_T

我们直接枚举每一种情况（这里用next_permutation，全排列）

然后判断是否符合情况（累加判断）

#include <cstdio>
#include <cstring>
#include <cmath>
#include <string>
#include <iostream>
#include <algorithm>
#include <queue>
using namespace std;
#define rep(i, n) for(int i=0; i<(n); ++i)
#define for1(i,a,n) for(int i=(a);i<=(n);++i)
#define for2(i,a,n) for(int i=(a);i<(n);++i)
#define for3(i,a,n) for(int i=(a);i>=(n);--i)
#define for4(i,a,n) for(int i=(a);i>(n);--i)
#define CC(i,a) memset(i,a,sizeof(i))
#define read(a) a=getint()
#define print(a) printf("%d", a)
#define dbg(x) cout << #x << " = " << x << endl
#define printarr(a, n, m) rep(aaa, n) { rep(bbb, m) cout << a[aaa][bbb]; cout << endl; }
inline const int getint() { int r=0, k=1; char c=getchar(); for(; c<'0'||c>'9'; c=getchar()) if(c=='-') k=-1; for(; c>='0'&&c<='9'; c=getchar()) r=r*10+c-'0'; return k*r; }
inline const int max(const int &a, const int &b) { return a>b?a:b; }
inline const int min(const int &a, const int &b) { return a<b?a:b; }

int n, m;
int a[15], f[15];
int main() {
	read(n); read(m);
	for1(i, 1, n) a[i]=i;
	do {
		memcpy(f, a, sizeof(a));
		for1(i, 1, n-1) for3(j, i, 1) f[j]+=f[j+1];
		if(f[1]==m) {
			printf("%d", a[1]);
			for1(i, 2, n) printf(" %d", a[i]);
			puts("");
			break;
		}
	}while(next_permutation(a+1, a+1+n));
	return 0;
}

Description

FJ and his cows enjoy playing a mental game. They write down the numbers from 1 to N (1 <= N <= 10) in a certain order and then sum adjacent numbers to produce a new list with one fewer number. They repeat this until only a single number is left. For example, one instance of the game (when N=4) might go like this: 3 1 2 4 4 3 6 7 9 16 Behind FJ's back, the cows have started playing a more difficult game, in which they try to determine the starting sequence from only the final total and the number N. Unfortunately, the game is a bit above FJ's mental arithmetic capabilities. Write a program to help FJ play the game and keep up with the cows.

Input

* Line 1: Two space-separated integers: N and the final sum.

Output

* Line 1: An ordering of the integers 1..N that leads to the given sum. If there are multiple solutions, choose the one that is lexicographically least, i.e., that puts smaller numbers first.