USACO2016 Jan Bronze 3:Mowing the Field

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int w[4]={-1,0,1,0},w1[4]={0,1,0,-1};
int map[2000][2000],a[1001][2];
int sb(int x){
if(x=='N')return 0;
if(x=='E')return 1;
if(x=='S')return 2;
if(x=='W')return 3;
}
int main(){
int i,j,k,k1,n,y,ans,time;
char x;
scanf("%d",&n);
getchar();
for(i=1;i<=n;i++){
scanf("%c %d",&x,&y);
a[i][0]=sb(x);
a[i][1]=y;
getchar();
}
i=1000;j=1000;time=0;ans=100000000;
for(k=1;k<=n;k++){
//printf("%d\n",time);
for(k1=1;k1<=a[k][1];k1++){
time++;
i+=w[a[k][0]];
j+=w1[a[k][0]];
//if(i==993&&j==1000)printf("%d\n",time);
if(map[i][j]!=0){
if(time-map[i][j]<ans)ans=time-map[i][j];
}
map[i][j]=time;
}
}

if(ans==100000000)printf("-1\n");
else printf("%d\n",ans);

return 0;
}