本文主要是介绍染色 HYSBZ - 2243，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
https://www.lydsy.com/JudgeOnline/problem.php?id=2243
树链剖分加区间合并 每个节点维护最左边和最右边的颜色以及当前区间的总段数 最难处理的地方在于一条链会被剖分成很多小段 需要将衔接部分处理好
#include <bits/stdc++.h>
using namespace std;struct node1
{int v;int next;
};struct node2
{int l;int r;int left;int right;int val;int laz;
};node1 edge[200010];
node2 tree[400010];
int clr[100010],first[100010],fa[100010],deep[100010],sum[100010],son[100010],top[100010],mp1[100010],mp2[100010];
int n,q,num,ans,pre,lc,rc;void addedge(int u,int v)
{edge[num].v=v;edge[num].next=first[u];first[u]=num++;
}void dfsI(int cur)
{int i,v;sum[cur]=1,son[cur]=-1;for(i=first[cur];i!=-1;i=edge[i].next){v=edge[i].v;if(v!=fa[cur]){fa[v]=cur,deep[v]=deep[cur]+1;dfsI(v);sum[cur]+=sum[v];if(son[cur]==-1||sum[son[cur]]<sum[v]){son[cur]=v;}}}
}void dfsII(int cur,int tp)
{int i,v;num++;top[cur]=tp,mp1[cur]=num,mp2[num]=cur;if(son[cur]==-1) return;dfsII(son[cur],tp);for(i=first[cur];i!=-1;i=edge[i].next){v=edge[i].v;if(v!=fa[cur]&&v!=son[cur]){dfsII(v,v);}}
}void pushup(int cur)
{tree[cur].left=tree[2*cur].left,tree[cur].right=tree[2*cur+1].right;tree[cur].val=tree[2*cur].val+tree[2*cur+1].val;if(tree[2*cur].right==tree[2*cur+1].left) tree[cur].val--;
}void pushdown(int cur)
{if(tree[cur].laz!=-1){tree[2*cur].left=tree[2*cur].right=tree[cur].laz;tree[2*cur].val=1;tree[2*cur].laz=tree[cur].laz;tree[2*cur+1].left=tree[2*cur+1].right=tree[cur].laz;tree[2*cur+1].val=1;tree[2*cur+1].laz=tree[cur].laz;tree[cur].laz=-1;}
}void build(int l,int r,int cur)
{int m;tree[cur].l=l;tree[cur].r=r;tree[cur].left=0;tree[cur].right=0;tree[cur].val=0;tree[cur].laz=-1;if(l==r){tree[cur].left=clr[mp2[l]];tree[cur].right=clr[mp2[l]];tree[cur].val=1;return;}m=(l+r)/2;build(l,m,2*cur);build(m+1,r,2*cur+1);pushup(cur);
}void updateII(int pl,int pr,int c,int cur)
{if(pl<=tree[cur].l&&tree[cur].r<=pr){tree[cur].left=tree[cur].right=c;tree[cur].val=1;tree[cur].laz=c;return;}pushdown(cur);if(pl<=tree[2*cur].r) updateII(pl,pr,c,2*cur);if(pr>=tree[2*cur+1].l) updateII(pl,pr,c,2*cur+1);pushup(cur);
}void updateI(int u,int v,int c)
{while(top[u]!=top[v]){if(deep[top[u]]<deep[top[v]]) swap(u,v);updateII(mp1[top[u]],mp1[u],c,1);u=fa[top[u]];}if(deep[u]<deep[v]) swap(u,v);updateII(mp1[v],mp1[u],c,1);
}int getlca(int u,int v)
{while(top[u]!=top[v]){if(deep[top[u]]<deep[top[v]]) swap(u,v);u=fa[top[u]];}if(deep[u]<deep[v]) return u;else return v;
}void queryII(int pl,int pr,int cur)
{if(pl<=tree[cur].l&&tree[cur].r<=pr){ans+=tree[cur].val;if(tree[cur].left==rc) ans--;if(lc==-1) lc=tree[cur].left;rc=tree[cur].right;return;}pushdown(cur);if(pl<=tree[2*cur].r) queryII(pl,pr,2*cur);if(pr>=tree[2*cur+1].l) queryII(pl,pr,2*cur+1);
}void queryI(int u,int v)
{int lca;ans=0,lca=getlca(u,v);pre=-1;while(top[u]!=top[lca]){lc=-1,rc=-1;queryII(mp1[top[u]],mp1[u],1);u=fa[top[u]];if(rc==pre) ans--;pre=lc;}lc=-1,rc=-1;queryII(mp1[lca],mp1[u],1);if(rc==pre) ans--;pre=-1;while(top[v]!=top[lca]){lc=-1,rc=-1;queryII(mp1[top[v]],mp1[v],1);v=fa[top[v]];if(rc==pre) ans--;pre=lc;}lc=-1,rc=-1;queryII(mp1[lca],mp1[v],1);if(rc==pre) ans--;ans--;
}int main()
{int n,q,u,v,c,i;char op[10];while(scanf("%d%d",&n,&q)!=EOF){for(i=1;i<=n;i++){scanf("%d",&clr[i]);}memset(first,-1,sizeof(first));num=0;for(i=1;i<=n-1;i++){scanf("%d%d",&u,&v);addedge(u,v);addedge(v,u);}fa[1]=-1,deep[1]=1;dfsI(1);num=0;dfsII(1,1);build(1,n,1);while(q--){scanf("%s",op);if(op[0]=='C'){scanf("%d%d%d",&u,&v,&c);updateI(u,v,c);}else{scanf("%d%d",&u,&v);queryI(u,v);printf("%d\n",ans);}}}return 0;
}
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