15 day 1代碼

第一题

用堆维护。

#include <cstdio>
#include <algorithm>
#include <queue>
int n,i,f[400000],g[2][200000],j=0,k[400000];
int l,r;
bool cho;
struct pn{
	int l,r,n;
};
bool operator<(pn a,pn b){
	return a.n>b.n;
}
std::priority_queue<pn> q;
pn as,as1,as2;
int main(){
	freopen("minval.in","r",stdin);
	freopen("minval.out","w",stdout);
	scanf("%d",&n);
	for(i=0;i<n;++i) scanf("%d",&g[0][i]);
	for(i=0;i<n;++i) scanf("%d",&g[1][i]);
	std::sort(g[0],g[0]+n);
	std::sort(g[1],g[1]+n);
	as.l=0;
	as.r=0;
	as.n=g[0][0]+g[1][0];
	q.push(as);
	for(i=0;i<n;++i){
		as=q.top();
		q.pop();
		as1.l=as.l+1;
		as1.r=as.r;
		as1.n=g[0][as1.l]+g[1][as1.r];
		as2.l=as.l;
		as2.r=as.r+1;
		as2.n=g[0][as2.l]+g[1][as2.r];
		printf("%d ",as.n);
		q.push(as1);
		q.push(as2);
	}
	return 0;
}

第二题

连通性判定+二分图

#include <cstdio>
#include <cstring>
int f[200000],d,i,j,m,n,s,t,tt,a,b,pl,h[200000];
int q[200000],qh,qt;
bool f2;
struct edge{
	int t,n;
} edges[2000000];
inline void addedge(int f,int t){
	edges[++pl].n=h[f];
	edges[ pl ].t= t  ;
	h[f]=pl;
} 
int main(){
	freopen("catch.in","r",stdin);
	freopen("catch.out","w",stdout);
	scanf("%d",&tt);
	while(tt--){
		++j;
		memset(f,0,sizeof f);
		memset(h,0,sizeof h);
		pl=0;
		qh=qt=0;
		scanf("%d%d%d",&n,&m,&s);
		for(i=0;i<m;++i){
			scanf("%d%d",&a,&b);
			addedge(a,b);
			addedge(b,a);
		}
		q[qt++]=s;
		f2=false;
		f[s]=1;
		--n;
		while(qh!=qt){
			i=q[qh++];
			for(d=h[i];d;d=edges[d].n){
				t=edges[d].t;
				if(!f[t]){
					f[t]=3-f[i];
					q[qt++]=t;
					--n;
				}else{
					if(f[i]==f[t]) f2=true;//not bicolorable
				}
			}
		}
		if(!f2){
			printf("Case %d: NO
",j);
		}else{
			if(n) printf("Case %d: NO
",j); else printf("Case %d: YES
",j);
		}
	}
	return 0;
}

第三題：二分答案加判定

#include <cstdio>
#include <cstring>
struct edge{
	int t,n,w;
} e[300000];
int h[20000],pl;
inline void addedge(int f,int t,int w){
	e[++pl].t=t;
	e[pl].n=h[f];
	e[pl].w=w;
	h[f]=pl;
}
int n,m,u,v,s,i,j,k;
int left,right,mid,ans;
int cost[20000];
int q[100000],qh,qt;
bool iq[20000];
int f[20000];
int ka,kb,ww;
int v0,v1,e0;
void spfa(int mma){
	memset(f,-1,sizeof f);
	memset(iq,0,sizeof iq);
	qh=qt=0;
	q[qt++]=u;
	f[u]=0;
	while(qh!=qt){
		v0=q[qh++];
		iq[v0]=false;
		for(e0=h[v0];e0;e0=e[e0].n){
			v1=e[e0].t;
			if(cost[v1]>mma) continue;
			if(f[v1]==-1 || f[v1] > f[v0] + e[e0].w){
				f[v1] = f[v0] + e[e0].w;
				if(!iq[v1]){
					iq[v1]=true;
					q[qt++]=v1;
				}
			}
		}
	}
}
int main(){
	freopen("cost.in","r",stdin);
	freopen("cost.out","w",stdout);
	scanf("%d%d%d%d%d",&n,&m,&u,&v,&s);
	left=0x7fffffff;
	for(i=1;i<=n;++i){
		scanf("%d",cost+i);
		if(cost[i]<left) left=cost[i];
		if(cost[i]>right) right=cost[i];
	}
	for(i=1;i<=m;++i){
		scanf("%d%d%d",&ka,&kb,&ww);
		addedge(ka,kb,ww);
		addedge(kb,ka,ww);
	}
	spfa(right);
	if(f[v]==-1 || f[v] > s){
		printf("-1
");
		return 0;
	}
	while(left<=right){
		mid=(left+right)/2;
		spfa(mid);
		if( f[v] == -1 || f[v] > s ){
			left=mid+1;
		}else{
			right=mid-1;
			ans=mid;
		}
	}
	printf("%d
",ans);
	return 0;
}

更新：修復了exceed 32bit int的bug

#include <cstdio>
#include <cstring>
struct edge{
	int t,n,w;
} e[300000];
long long h[20000],pl;
inline void addedge(int f,int t,int w){
	e[++pl].t=t;
	e[pl].n=h[f];
	e[pl].w=w;
	h[f]=pl;
}
long long n,m,u,v,s,i,j,k;
long long left,right,mid,ans;
long long cost[20000];
long long q[100000],qh,qt;
bool iq[20000];
long long f[20000];
long long ka,kb,ww;
long long v0,v1,e0;
void spfa(int mma){
	memset(f,-1,sizeof f);
	memset(iq,0,sizeof iq);
	qh=qt=0;
	q[qt++]=u;
	f[u]=0;
	while(qh!=qt){
		v0=q[qh++];
		iq[v0]=false;
		for(e0=h[v0];e0;e0=e[e0].n){
			v1=e[e0].t;
			if(cost[v1]>mma) continue;
			if(f[v1]==-1 || f[v1] > f[v0] + e[e0].w){
				f[v1] = f[v0] + e[e0].w;
				if(!iq[v1]){
					iq[v1]=true;
					q[qt++]=v1;
				}
			}
		}
	}
}
int main(){
	freopen("cost.in","r",stdin);
	freopen("cost.out","w",stdout);
	scanf("%lld%lld%lld%lld%lld",&n,&m,&u,&v,&s);
	left=0x7fffffff;
	for(i=1;i<=n;++i){
		scanf("%lld",cost+i);
		if(cost[i]<left) left=cost[i];
		if(cost[i]>right) right=cost[i];
	}
	for(i=1;i<=m;++i){
		scanf("%lld%lld%lld",&ka,&kb,&ww);
		addedge(ka,kb,ww);
		addedge(kb,ka,ww);
	}
	spfa(right);
	if(f[v]==-1 || f[v] > s){
		printf("-1
");
		return 0;
	}
	while(left<=right){
		mid=(left+right)/2;
		spfa(mid);
		if( f[v] == -1 || f[v] > s ){
			left=mid+1;
		}else{
			right=mid-1;
			ans=mid;
		}
	}
	printf("%lld
",ans);
	return 0;
}