洛谷 P2664 树上游戏

最新推荐文章于 2022-11-02 20:37:24 发布

吴俊达9812

最新推荐文章于 2022-11-02 20:37:24 发布

阅读量207

点赞数

CC 4.0 BY-SA版权

分类专栏：点分治树上差分文章标签：点分治树上差分

本文链接：https://blog.youkuaiyun.com/ehdhg13455/article/details/95645602

树上差分同时被 2 个专栏收录

8 篇文章

订阅专栏

点分治

6 篇文章

订阅专栏

博主分享了树上差分的80分代码，却找不到代码错误所在。涉及树上差分相关信息技术内容。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

#include <bits/stdc++.h>
using namespace std;
typedef long long lint;
typedef long long LL;
const lint maxn = 200000 + 5;
const lint maxm = 400000 + 5;
const lint inf = 0x3f3f3f3f3f;
lint vis[maxn],g[maxn],sz[maxn],root,sum,c[maxn];
vector<lint> ve[maxn];
void add_edge( lint x,lint y ){
    ve[x].push_back(y);
}
lint sz_sum,color_cnt,pre_color_sum,color[maxn],in_st[maxn],ans[maxn];
void dfs_cnt( lint x,lint f,lint flag ){
    sz[x]=1;
    if( !in_st[c[x] ] ){
        color_cnt++;
        pre_color_sum -= color[ c[x] ];
    }
    in_st[ c[x] ]++;
    if( !in_st[c[root] ] )
    ans[x] += pre_color_sum-color[ c[root] ] + (color_cnt+1) *( sz_sum+flag );
    else ans[x] += pre_color_sum + color_cnt * (sz_sum+flag );
    for( lint i = 0;i < ve[x].size();i++ ){
        lint y = ve[x][i];
        if( vis[y] || y==f ) continue;
        dfs_cnt( y,x,flag );
        sz[x] +=sz[y];
    }
    in_st[ c[x] ]--;
    if(!in_st[ c[x] ] ){
        color_cnt--;
        pre_color_sum += color[ c[x] ];
    }
}
void dfs_init( lint x,lint f ){
    if(!in_st[c[x]] ){
        color[ c[x] ] += sz[x];
        pre_color_sum += sz[x];
    }
    in_st[ c[x] ]++;
    for( lint i = 0;i < ve[x].size();i++ ){
        lint y = ve[x][i];
        if( y == f || vis[y] ) continue;
        dfs_init(y,x);
    }
    in_st[c[x]]--;
}
void dfs_init2( lint x,lint f ){
    color[c[x] ]=0;
    for( lint i = 0;i < ve[x].size();i++ ){
        lint y = ve[x][i];
        if( vis[y] || y == f ) continue;
        dfs_init2(y,x);
    }
}
void get_root(lint x,lint f)
{
    sz[x]=1;g[x]=0;
    for(int i = 0; i < ve[x].size() ;i++){
        lint y = ve[x][i];
        if( vis[y] || y == f ) continue;
        get_root(y,x);
        g[x]=max(g[x],sz[y]);
        sz[x]+=sz[y];
    }
    g[x]=max(g[x],sum-sz[x]);
    if(g[x]<g[root])root=x;
}
void dfs_div( lint x ){
    vis[x] = 1;
    sz_sum = 0;
    sz[x]=1;
    pre_color_sum=0;
    for( lint i = 0;i < ve[x].size();i++ ){
        lint  y = ve[x][i];
        if(vis[y]) continue;
        dfs_cnt(y,x,1);
        sz[x]+=sz[y];
        dfs_init( y,x );
        sz_sum += sz[y];
    }
    ans[x] += pre_color_sum +sz[x]-1 -color[ c[x] ] ;
    sz_sum = 0;
    pre_color_sum=0;
    dfs_init2(x,0);
    for( lint i =ve[x].size()-1;i >= 0;i-- ){
        lint  y= ve[x][i];
        if(vis[y]) continue;
        dfs_cnt(y,x,0);
        dfs_init(y,x);
        sz_sum += sz[y];
    }
    dfs_init2(x,0);
    for( lint i = 0; i < ve[x].size() ;i++ ){
        lint y = ve[x][i];
        if( vis[y] ) continue;
        root = 0;sum = sz[y];
        get_root( y,x );
        dfs_div( root );
    }
}
int main() {
    lint n;
    scanf("%lld",&n);
    for( lint i = 1;i <= n;i++ ) scanf("%lld",&c[i]);
    for( lint x,y,i = 1;i <= n-1;i++ ){
        scanf("%lld%lld",&x,&y);
        add_edge(x,y);add_edge(y,x);
    }
    g[0]=n;sum = n;
    get_root(1,0);
    dfs_div(root);
    for( lint i = 1;i <= n;i++ ){
        printf("%lld\n",ans[i]+1);
    }
    return 0;
}

这是树上差分的80分代码，实在看不出来哪错了QAQ

#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef LL lint;
const lint maxn = 1000005;
const lint maxm = 2000005;
lint color[maxn],c[maxn];
lint he[maxn],ver[maxm],ne[maxm],tot,val[maxn],n;
void init(){
    tot = 1;
}
void add( lint x,lint y ){
    ver[++tot] = y;
    ne[tot] = he[x];
    he[x]=tot;
};
lint sz[maxn];
void dfs( lint x,lint f ){
    sz[x]=1;
    for( lint cure = he[x];cure;cure = ne[cure] ){
        lint y = ver[cure];
        if( y == f ) continue;
        lint pre = color[ c[x] ];
        dfs(y,x);
        sz[x] += sz[y];
        val[y] = sz[y]  - (color[ c[x] ] - pre);
        color[ c[x] ] += sz[y] - ( color[ c[x] ]-pre ) ;
    }
    color[ c[x] ]++;
}
lint color_val[maxn],v[maxn];
void dfs_pre( lint x,lint f ){
    v[x] += val[x];
    v[x] -= color_val[ c[x] ];
    lint pre = color_val[ c[f] ];
    color_val[ c[f] ] = val[x];
    for( lint cure = he[x];cure;cure = ne[cure] ){
        lint y = ver[cure];
        if( y == f ) continue;
        dfs_pre(y,x);
    }
    color_val[ c[f] ] = pre;
}
lint cur = 0;
lint res[maxn];
void dfs_cal( lint x,lint f ){
    lint pre = cur;
    cur += v[x];
    res[x]=cur;
    for( lint cure = he[x];cure;cure = ne[cure] ){
        lint y = ver[cure];
        if( y == f ) continue;
        dfs_cal(y,x);
    }
    cur = pre;
}
lint in_st[maxn],vis[maxn];
void dfs_pre2( lint x,lint f ){
    if( !in_st[ c[x] ] ){
        v[ x ] -= n-color[ c[x] ];
    }
    in_st[ c[x] ]++;
    for( lint cure = he[x];cure;cure = ne[cure] ){
        lint y = ver[cure];
        if( y == f ) continue;
        dfs_pre2(y,x);
    }
    in_st[ c[x] ]--;
}
int main(){
    lint color_cnt = 0;
    scanf("%lld",&n);
    init();
    for( lint i = 1;i <= n;i++ ) {
        scanf("%lld",&c[i]);
        if( !vis[ c[i] ] ){
            color_cnt++;
            vis[ c[i] ]=1;
        }
    }
    for( lint x,y,i = 1;i <=n-1;i++ ){
        scanf("%lld%lld",&x,&y);
        add(x,y);add(y,x);
    }
    dfs(1,0);
    in_st[ c[1] ] = 1;
    for( lint i = 1;i < maxn;i++ ) {
        if( vis[i] )
            cur += n-color[i];
    }
    dfs_pre2( 1,0 );
    dfs_pre(1,0);
    dfs_cal( 1,0 );
    for( lint i = 1;i <= n;i++ ){
        printf("%lld\n", n*color_cnt-res[i] );
    }
    return 0;
}