C++代码找问题大赛 I

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C++代码找问题大赛 I：

注意逝项： 本考试禁止复制（虽然我管不了）。

卷一：\color{#FADB14}CE

找出以下代码的编译问题(P1001)

1.

#include<bits/stdc++.h>

int a,b;
int main(){
    cin>>a>>b;
    cout<<a+b;
    return 0;
}

2.

#include<bits/stdc++.h>>
using namespace std;
int a,b;
int main(){
    cin>>a>>b;
    cout<<a+b;
    return 0;
}

3.

#include<bits/stdc++.h>
using namespace std;
int a,b;
int main(){
    cin<<a<<b;
    cout>>a+b;
    return 0;
}

4.

#include<bit/stdc++.h>
using namespace std;
int a,b;
int main(){
    cin>>a>>b;
    cout<<a+b;
    return 0;
}

5.

#include<bits/stdc++.h>
using namesapce std;
int a,b;
int main(){
    cin>>a>>b;
    cout<<a+b;
    return 0;
}

找出以下代码的编译问题(P3379)

1.

#include<bits/stdc++.h>
using namespace std;

int read(){
    int x=0,f=1;
    char c=getchar();
    while(c>57||c<48){
        if(c==45) f=-1;
        c=getchar();
    }
    while(c<58&&c>47){
        x=(x<<1)+(x<<3)+(c^48);
        c=getchar();
    }
    return x*f;
}
void write(int x){
    if(x<0) putchar(45),x=-x;
    if(x>9) write(x/10);
    putchar(x%10|48);
}

int n=read(),m=read();
int r=read();
int v[500005];

int h[500005],to[1000005],nxt[1000005],idx;
void add(int x,int y){to[++idx]=y;nxt[idx]=h[x];h[x]=idx;}

int fa[500005],sz[500005],son[500005],dep[500005];
void dfs1(int x,int fat){
    fa[x]=fat;
    dep[x]=dep[fat]+1;
    sz[x]=1;
    for(int ep=h[x];ep;ep=nxt[ep]){
        if(to[ep]==fat) continue;
        dfs1(to[ep],x);
        if(sz[to[ep]]>sz[son[x]]) son[x]=to[ep];
        sz[x]+=sz[to[ep]];
    }
}
int top[500005],dfn[500005],dcnt;
void dfs2(int x,int tp){
    dfn[x]=++dcnt;
    top[x]=tp;
    if(son[x]==0) return;
    dfs2(son[x],tp);
    for(int ep=h[x];ep;ep=nxt[ep]){
        if(to[ep]!=fa[x]&&to[ep]!=son[x]) dfs2(to[ep],to[ep]);
    }
}

int LCA(int x,int y){
    while(top[x]!=top[y]){
        if(dep[top[x]]<dep[top[y]]) swap(x,y);
        x=fa[top[x]];
    }
    return dep[x]<dep[y]?x:y;
}

int main(){
    for(int i=1;i<n;i++){
        int x=read(),y=read();
        add(x,y);
        add(y,x);
    }
    dfs1(r);
    dfs2(r,r);
    for(int i=1;i<=m;i++){
        int x=read(),y=read();
        write(LCA(x,y)),putchar(10);
    }
}

2.

#include<bits/stdc++.h>
using namespace std;

void read(){
    int x=0,f=1;
    char c=getchar();
    while(c>57||c<48){
        if(c==45) f=-1;
        c=getchar();
    }
    while(c<58&&c>47){
        x=(x<<1)+(x<<3)+(c^48);
        c=getchar();
    }
    return x*f;
}
void write(int x){
    if(x<0) putchar(45),x=-x;
    if(x>9) write(x/10);
    putchar(x%10|48);
}

int n=read(),m=read();
int r=read();
int v[500005];

int h[500005],to[1000005],nxt[1000005],idx;
void add(int x,int y){to[++idx]=y;nxt[idx]=h[x];h[x]=idx;}

int fa[500005],sz[500005],son[500005],dep[500005];
void dfs1(int x,int fat=0){
    fa[x]=fat;
    dep[x]=dep[fat]+1;
    sz[x]=1;
    for(int ep=h[x];ep;ep=nxt[ep]){
        if(to[ep]==fat) continue;
        dfs1(to[ep],x);
        if(sz[to[ep]]>sz[son[x]]) son[x]=to[ep];
        sz[x]+=sz[to[ep]];
    }
}
int top[500005],dfn[500005],dcnt;
void dfs2(int x,int tp){
    dfn[x]=++dcnt;
    top[x]=tp;
    if(son[x]==0) return;
    dfs2(son[x],tp);
    for(int ep=h[x];ep;ep=nxt[ep]){
        if(to[ep]!=fa[x]&&to[ep]!=son[x]) dfs2(to[ep],to[ep]);
    }
}

int LCA(int x,int y){
    while(top[x]!=top[y]){
        if(dep[top[x]]<dep[top[y]]) swap(x,y);
        x=fa[top[x]];
    }
    return dep[x]<dep[y]?x:y;
}

int main(){
    for(int i=1;i<n;i++){
        int x=read(),y=read();
        add(x,y);
        add(y,x);
    }
    dfs1(r);
    dfs2(r,r);
    for(int i=1;i<=m;i++){
        int x=read(),y=read();
        write(LCA(x,y)),putchar(10);
    }
}

3.

#include<bits/stdc++.h>
using namespace std;

int read(){
    int x=0,f=1;
    char c=getchar();
    while(c>57||c<48){
        if(c==45) f=-1;
        c=getchar();
    }
    while(c<58&&c>47){
        x=(x<<1)+(x<<3)+(c^48);
        c=getchar();
    }
    return x*f;
}
void write(int x){
    if(x<0) putchar(45),x=-x;
    if(x>9) write(x/10);
    putchar(x%10|48);
}

int n=read(),m=read();
int r=read();
int v[500005];

int h[500005],to[1000005],nxt[1000005],idx;
void add(int x,int y){to[++idx]=y;nxt[idx]=h[x];h[x]=idx;}

int fa[500005],sz[500005],son[500005],dep[500005];
void dfs1(int x,int fat=0){
    fa[x]=fat;
    dep[x]=dep[fat]+1;
    sz[x]=1;
    for(int ep=h[x];ep;ep=nxt[ep]){
        if(to[ep]==fat) continue;
        dfs1(to[ep],x);
        if(sz[to[ep]]>sz[son[x]]) son[x]=to[ep];
        sz[x]+=sz[to[ep]];
    }
}
int top[500005],dfn[500005],dcnt;
void dfs2(int x,int tp){
    dfn[x]=++dcnt;
    top[x]=tp;
    if(son[x]==0) return;
    dfs2(son[x],tp);
    for(int ep=h[x];ep;ep=nxt[ep]){
        if(to[ep]!=fa[x]&&to[ep]!=son[x]) dfs2(to[ep],to[ep]);
    }
}

int LCA(int x,int y){
    while(top[x]!=top[y]){
        if(dep[top[x]]<dep[top[y]]) swap(x,y);
        x=fa[top[x]];
    }
    return dep[x]<dep[y]?x:y;
}

int main(){
    for(int i=1;i<n;i++){
        int x=read(),y=read();
        add(x,y);
        add(y,x);
    }
    dfs1(r);
    dfs2(r,r);
    for(int i=1;i<=m;i++){
        int x=read(),y=read();
        write(LCA(x,y)),putcahr(10);
    }
}

4.

#include<bits/stdc++.h>
using namespace std;

int read(){
    int x=0,f=1;
    char c=getchar();
    while(c>57||c<48){
        if(c==45) f=-1;
        c=getchar();
    }
    while(c<58&&c>47){
        x=(x<<1)+(x<<3)+(c^48);
        c=getchar();
    }
    return x*f;
}
void write(int x){
    if(x<0) putchar(45),x=-x;
    if(x>9) write(x/10);
    putchar(x%10|48);
}

int n=read(),m=read();
int r=read();
int v[500005];

int h[500005],to[1000005],nxt[1000005],idx;
void add(int x,int y){to[++idx]=y;nxt[idx]=h[x];h[x]=idx}

int fa[500005],sz[500005],son[500005],dep[500005];
void dfs1(int x,int fat=0){
    fa[x]=fat;
    dep[x]=dep[fat]+1;
    sz[x]=1;
    for(int ep=h[x];ep;ep=nxt[ep]){
        if(to[ep]==fat) continue;
        dfs1(to[ep],x);
        if(sz[to[ep]]>sz[son[x]]) son[x]=to[ep];
        sz[x]+=sz[to[ep]];
    }
}
int top[500005],dfn[500005],dcnt;
void dfs2(int x,int tp){
    dfn[x]=++dcnt;
    top[x]=tp;
    if(son[x]==0) return;
    dfs2(son[x],tp);
    for(int ep=h[x];ep;ep=nxt[ep]){
        if(to[ep]!=fa[x]&&to[ep]!=son[x]) dfs2(to[ep],to[ep]);
    }
}

int LCA(int x,int y){
    while(top[x]!=top[y]){
        if(dep[top[x]]<dep[top[y]]) swap(x,y);
        x=fa[top[x]];
    }
    return dep[x]<dep[y]?x:y;
}

int main(){
    for(int i=1;i<n;i++){
        int x=read(),y=read();
        add(x,y);
        add(y,x);
    }
    dfs1(r);
    dfs2(r,r);
    for(int i=1;i<=m;i++){
        int x=read(),y=read();
        write(LCA(x,y)),putchar(10);
    }
}

5.

#include<bits/stdc++.h>
using namespace std;

int read(){
    int x=0,f=1;
    char c=getchar();
    while(c>57||c<48){
        if(c==45) f=-1;
        c=getchar();
    }
    while(c<58&&c>47){
        x=(x<<1)+(x<<3)+(c^48);
        c=getchar();
    }
    return x*f;
}
void write(int x){
    if(x<0) putchar(45),x=-x;
    if(x>9) write(x/10);
    putchar(x%10|48);
}

int n=read(),m=read();
int r=read();
int v[500005];

int h[500005],to[1000005],nxt[1000005],idx;
void add(int x,int y){to[++idx]=y;nxt[idx]=h[x];h[x]=idx;}

int fa[500005],sz[500005],son[500005],dep[500005];
void dfs1(int x,int fat=0){
    fa[x]=fat;
    dep[x]=dep[fat]+1;
    sz[x]=1;
    for(int ep=h[x];ep;ep=nxt[ep]){
        if(to[ep]==fat) comtinue;
        dfs1(to[ep],x);
        if(sz[to[ep]]>sz[son[x]]) son[x]=to[ep];
        sz[x]+=sz[to[ep]];
    }
}
int top[500005],dfn[500005],dcnt;
void dfs2(int x,int tp){
    dfn[x]=++dcnt;
    top[x]=tp;
    if(son[x]==0) return;
    dfs2(son[x],tp);
    for(int ep=h[x];ep;ep=nxt[ep]){
        if(to[ep]!=fa[x]&&to[ep]!=son[x]) dfs2(to[ep],to[ep]);
    }
}

int LCA(int x,int y){
    while(top[x]!=top[y]){
        if(dep[top[x]]<dep[top[y]]) swap(x,y);
        x=fa[top[x]];
    }
    return dep[x]<dep[y]?x:y;
}

int main(){
    for(int i=1;i<n;i++){
        int x=read(),y=read();
        add(x,y);
        add(y,x);
    }
    dfs1(r);
    dfs2(r,r);
    for(int i=1;i<=m;i++){
        int x=read(),y=read();
        write(LCA(x,y)),putchar(10);
    }
}

答案

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