求调awa

#include<cstdio>
#include<string>
#include<cstring>

using namespace std;

int max(int a,int b) {
	return a>b?a:b;
}
int min(int a,int b) {
	return a<b?a:b;
}

inline int read() {
	int ret=0,f=1;
	char c=getchar();
	for(; c<'0'||c>'9'; c=getchar()) if(c=='-') f=-f;
	for(; c>='0'&&c<='9'; c=getchar()) ret=ret*10+c-'0';
	return ret*f;
}
const int maxn=60;
int n,c;
int p[maxn],e[maxn],sum[maxn];
int f[maxn][maxn][5];
signed main(void) {

	n=read();
	c=read();
	memset(f,127,sizeof(f));

	for(int i=1; i<=n; i++) {
		p[i]=read();
		e[i]=read();
		sum[i]=sum[i-1]+e[i];
	}

	f[c][c][0]=f[c][c][1]=0;

	for(int l=2; l<=n; l++) {
		for(int i=1; i+l-1<=n; i++) {
			int j=i+l-1;

			f[i][j][0]=min(f[i+1][j][0]+(p[i+1]-p[i])*(sum[n]+sum[i]-sum[j]),f[i+1][j][1]+(p[j]-p[i])*(sum[n]+sum[i]-sum[j]));
			f[i][j][1]=min(f[i][j-1][1]+(p[j]-p[i])*(sum[i-1]+sum[n]-sum[j-1]),f[i][j-1][1]+(p[j]-p[j-1])*(sum[i-1]+sum[n]-sum[j-1]));
		}
	}

	int ans=min(f[1][n][0],f[1][n][1]);

	printf("%d\n",ans);

	return 0;
}