usaco /the second wave

bzoj4582:简单递推题。

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
#define REP(i,s,t) for(int i=s;i<=t;i++)
int read(){
	int x=0;char c=getchar();
	while(!isdigit(c)) c=getchar();
	while(isdigit(c)) x=x*10+c-'0',c=getchar();
	return x;
}
const int nmax=50005;
int a[nmax],rmax[nmax],res[nmax];
int main(){
	int n=read(),k=read();
	REP(i,1,n) a[i]=read();
	sort(a+1,a+n+1);
	REP(i,1,n){
		int tmp=i;
		while(a[tmp]-a[i]<=k&&tmp<=n) tmp++;
		rmax[i]=tmp-i;
	}
	for(int i=n;i;i--) res[i]=max(res[i+1],rmax[i]);
	int ans=-1;
	REP(i,1,n) ans=max(ans,rmax[i]+res[i+rmax[i]]);
	printf("%d\n",ans);
	return 0;
}

bzoj4525:二分答案+贪心判断。

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
#define REP(i,s,t) for(int i=s;i<=t;i++)
#define clr(x,c) memset(x,c,sizeof(x))
const int nmax=50005;
int a[nmax],n,m;
int read(){
	int x=0;char c=getchar();bool f=true;
	while(!isdigit(c)){
		if(c=='-') f=false;c=getchar();
	}
	while(isdigit(c)) x=x*10+c-'0',c=getchar();
	return f?x:-x;
}
bool check(int x){
	int ans=0;
	REP(i,1,n){
		int temp=a[i];
		while(a[i]-temp<=x*2&&i<=n) i++;
		i--;
		ans++;
	}
	if(ans<=m) return true;
	return false;
}
int main(){
	n=read(),m=read();
	REP(i,1,n) a[i]=read();
	sort(a+1,a+n+1);
	int l=0,r=1000000000,mid,ans;
	while(l<=r){
		mid=(l+r)>>1;
		if(check(mid)) ans=mid,r=mid-1;
		else l=mid+1;
	}
	printf("%d\n",ans);
	return 0;
}

bzoj4511:模拟。。。

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iostream>
using namespace std;
int x;char c;
int read(){
	x=0;c=getchar();
	while(!isdigit(c)) c=getchar();
	while(isdigit(c)) x=x*10+c-'0',c=getchar();
	return x;
}
int a[7],n,tmp,sum=0,ans=0;
int main(){
	memset(a,-1,sizeof(a));
	a[0]=0;
	n=read();
	for(int i=1;i<=n;i++){
		tmp=read();
		sum+=tmp,sum%=7;
		if(a[sum]!=-1) ans=max(ans,i-a[sum]);
		else a[sum]=i;
	}
	printf("%d\n",ans);
	return 0;
}

bzoj4397:模拟。。。

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
#define REP(i,s,t) for(int i=1;i<=t;i++)
int read(){
	int x=0;char c=getchar();
	while(!isdigit(c)) c=getchar();
	while(isdigit(c)) x=x*10+c-'0',c=getchar();
	return x;
}
const int nmax=100005;
int a[nmax],b[nmax],c[nmax];
int main(){
	int n=read(),m=read();
	REP(i,1,n) {
		a[i]=a[i-1],b[i]=b[i-1],c[i]=c[i-1];
		int tmp=read();
		if(tmp==1) a[i]++;
		else if(tmp==2) b[i]++;
		else c[i]++;
	}
	REP(i,1,m){
		int s=read(),t=read();
		printf("%d %d %d\n",a[t]-a[s-1],b[t]-b[s-1],c[t]-c[s-1]);
	}
	return 0;
}

bzoj4396:简单递推题。。。

#include<cstdio>
#include<iostream>
using namespace std;
const int nmax=100005;
bool vis[nmax];
int read(){
	int x=0;char c=getchar();
	while(!isdigit(c)) c=getchar();
	while(isdigit(c)) x=x*10+c-'0',c=getchar();
	return x;
}
int main(){
	int n=read();
	for(int i=1;i<=n;i++) vis[read()]=true;
	n+=n;
	int l=1,ans=0;
	for(int i=1;i<=n;i++) if(!vis[i]){
		while(!vis[l]) l++;
		if(l<i) l++,ans++;
	}
	printf("%d\n",ans);
	return 0;
}