USACO(含training section)水题合集[5/未完待续]

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
const int N=165,L=1e5;
struct fr{
int a,b;
fr(int q=0,int w=1):a(q),b(w){}
}f[L];
int n,cnt=0;
inline bool cmp(fr &x,fr &y){
return (double)x.a/x.b<(double)y.a/y.b;
}
inline int gcd(int a,int b){
return b==0?a:gcd(b,a%b);
}
int main(){
cin>>n;
for(int i=0;i<=n;i++)
for(int j=i+1;j<=n;j++)
if(gcd(i,j)==1)
f[++cnt]=fr(i,j);
sort(f+1,f+1+cnt,cmp);
for(int i=1;i<=cnt;i++)
printf("%d/%d\n",f[i].a,f[i].b);
cout<<"1/1";
}

#include<iostream>
#include<cstring>
#include<algorithm>
#include<cstdio>
using namespace std;
int r,d[1001][1001],a[1001][1001];
int dp(int i,int j){
if(d[i][j]>=0) return d[i][j];
return d[i][j]=a[i][j]+(i==r?0:max(dp(i+1,j),dp(i+1,j+1)));
}
int main(){
scanf("%d",&r);//cin>>r;
memset(d,-1,sizeof(d));
for(int i=1;i<=r;i++)
for(int j=1;j<=i;j++) scanf("%d",&a[i][j]);//cin>>a[i][j];
int ans=-10000000;
cout<<dp (1,1);
}

#include <iostream>
using namespace std;
const int N=12;
int n;
char a

,r

,t

;
bool ro90(char a

){
for(int i=1;i<=n;i++)
for(int j=1;j<=n;j++)
if(a[i][j]!=r[j][n-i+1]) return false;
return true;
}
bool ro180(char a

){
for(int i=1;i<=n;i++)
for(int j=1;j<=n;j++)
if(a[i][j]!=r[n-i+1][n-j+1]) return false;
return true;
}
bool ro270(char a

){
for(int i=1;i<=n;i++)
for(int j=1;j<=n;j++)
if(a[i][j]!=r[n-j+1][i]) return false;
return true;
}
void img(char a

,char t

){
for(int i=1;i<=n;i++)
for(int j=1;j<=n;j++)
t[i][n-j+1]=a[i][j];
}
bool check(char r

,char t

){
for(int i=1;i<=n;i++)
for(int j=1;j<=n;j++)
if(r[i][j]!=t[i][j]) return false;
return true;
}

int solve(){
if(ro90(a)) return 1;
if(ro180(a)) return 2;
if(ro270(a)) return 3;
img(a,t);
if(check(r,t)) return 4;
if(ro90(t)) return 5;
if(ro180(t)) return 5;
if(ro270(t)) return 5;
if(check(r,t)) return 6;
return 7;
}
int main(int argc, const char * argv[]) {
cin>>n;
for(int i=1;i<=n;i++)
for(int j=1;j<=n;j++)cin>>a[i][j];

for(int i=1;i<=n;i++)
for(int j=1;j<=n;j++)cin>>r[i][j];

cout<<solve();

}

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int N=25;
int vis

;
int l[4],ta,tb,tc;
int ans
;
inline void fill(int &a,int &b,int num){
int tmp=min(l[num]-a,b);
a+=tmp;
b-=tmp;
}

void dfs(int a,int b,int c){//printf("%d %d %d\n",a,b,c);
if(vis[a][c]) return;
if(a==0) ans[c]=true;
vis[a][b][c]=1;

ta=a;tb=b;tc=c;//1
fill(ta,tb,1);dfs(ta,tb,tc);

ta=a;tb=b;tc=c;//2
fill(ta,tc,1);dfs(ta,tb,tc);

ta=a;tb=b;tc=c;//3
fill(tb,ta,2);dfs(ta,tb,tc);

ta=a;tb=b;tc=c;//4
fill(tb,tc,2);dfs(ta,tb,tc);

ta=a;tb=b;tc=c;//5
fill(tc,ta,3);dfs(ta,tb,tc);

ta=a;tb=b;tc=c;//6
fill(tc,tb,3);dfs(ta,tb,tc);
}
int main(){
cin>>l[1]>>l[2]>>l[3];
dfs(0,0,l[3]);
for(int i=0;i<=l[3];i++) if(ans[i]) cout<<i<<" ";

}

#include<iostream>
using namespace std;
int n,m,t,sx,sy,fx,fy,ans=0;int x,y;
int e[8][8],vis[8][8],dx[4]={-1,0,1,0},dy[4]={0,1,0,-1};
void dfs(int x,int y){
if(x<1||y<1||x>n||y>m) return;
if(e[x][y]) return;
if(x==fx&&y==fy) {ans++;return;}
if(vis[x][y]) return;
vis[x][y]=1;
for(int i=0;i<4;i++) dfs(x+dx[i],y+dy[i]);
vis[x][y]=0;
}
int main(){
cin>>n>>m>>t>>sx>>sy>>fx>>fy;
for(int i=0;i<t;i++) {cin>>x>>y;e[x][y]=1;}
dfs(sx,sy);
cout<<ans;
}