Alibaba UVA - 1632

#include<bits/stdc++.h>
#define inf 0x3f3f3f3f
using namespace std;

const int maxn = 1e4+10;

int kase = 0;

struct node {
    int pos,tim;
}treasure[maxn];

int n,f[maxn][maxn][2],vis[maxn][maxn][2];

bool cmp(const node& a,const node& b) {
    return a.pos<b.pos;
}

int dp(int x,int y,int z) {
    if(x==y) return 0;
    int& ans=f[x][y][z];
    if(vis[x][y][z]==kase) return ans;
    vis[x][y][z]=kase;
    ans=inf;
    if(z==0) ans=min(min(ans,dp(x+1,y,1)+treasure[y].pos-treasure[x].pos),dp(x+1,y,0)+treasure[x+1].pos-treasure[x].pos);
    else ans=min(min(ans,dp(x,y-1,1)+treasure[y].pos-treasure[y-1].pos),dp(x,y-1,0)+treasure[y].pos-treasure[x].pos);
    if(ans>=treasure[z==0?x:y].tim) ans=inf;
    return ans; 
}

int main() {
    //freopen("in.txt","r",stdin);
    while(scanf("%d",&n)!=EOF) {
        ++kase;
        for(int i=1;i<=n;i++) scanf("%d%d",&treasure[i].pos,&treasure[i].tim);
        //for(int i=1;i<=n;i++) f[i][i][0]=f[i][i][1]=0;
        //sort(treasure+1,treasure+1+n,cmp);
        int ans=min(dp(1,n,1),dp(1,n,0));
        if(ans==0x3f3f3f3f) printf("No solution\n");
        else printf("%d\n",ans);
    }
}