切木棍 Cutting Sticks

簡單的dp

//Serene
//紫書p278 切木棍 Cutting Sticks  
#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdlib>
#include<cstdio>
#include<cmath>
using namespace std;
const int maxn=50+10;
int l,n,p[maxn],dp[maxn][maxn];

int aa;char c;
int read() {
	aa=0;c=getchar();
	while(c<'0'||c>'9') c=getchar();
	while(c>='0'&&c<='9') aa=aa*10+c-'0',c=getchar();
	return aa;
}

int main() {
	l=read();
	while(l) {
		memset(p,0,sizeof(p));
		memset(dp,0x7f,sizeof(dp));
		n=read();dp[0][1]=0;p[n+1]=l;
		for(int i=1;i<=n;++i) p[i]=read(),dp[i][i+1]=0;
		for(int len=2;len<=n+1;++len)
			for(int i=0;i<=n+1-len;++i)
				for(int j=i+1;j<=i+len-1;++j) dp[i][i+len]=min(dp[i][i+len],dp[i][j]+dp[j][i+len]+p[i+len]-p[i]);
		printf("The minimum cutting is %d.\n",dp[0][n+1]);
		l=read();
	}
	return 0;
}