Zoj1610 count the colors classical line segment tree dyeing problem

Here are N values of X, Y, and C, which means that the interval [x, y] is colored in C, but the color will be covered, after the dyeing operation is complete, ask you how many segments each color has and output the color ID and segment count CNT

Classic problems, but I'm a bit confused. I didn't go to anyone else's. This method should be the most traditional and common, and the conventional open array record. Maybe the great gods have a higher-end method.

#include<iostream>#include<cstdio>#include<list>#include<algorithm>#include<cstring>#include<string>#include<queue>#include<stack>#include<map>#include<vector>#include<cmath>#include<memory.h>#include<set>#include<cctype>#define ll long long#define LL __int64#define eps 1e-8#define inf 0xfffffff//const LL INF = 1LL<<61;using namespace std;//vector<pair<int,int> > G;//typedef pair<int,int > P;//vector<pair<int,int> > ::iterator iter;////map<ll,int >mp;//map<ll,int >::iterator p;const int N = 8000 + 5;typedef struct Node {int l,r;int col;};Node tree[N * 4];int color[N];int ans[N];void init() {memset(color,-1,sizeof(color));memset(ans,0,sizeof(ans));}void build(int l,int r,int id) {tree[id].l = l;tree[id].r = r;tree[id].col = -1;if(l == r)return;int mid = (l + r)/2;build(l,mid,id<<1);build(mid+1,r,id<<1|1);}void cal(int id) {if(tree[id].col > -1) {tree[id<<1].col = tree[id].col;tree[id<<1|1].col = tree[id].col;tree[id].col = -1;}}void update(int l,int r,int id,int col) {if(tree[id].col == col)return;if(l <= tree[id].l && r >= tree[id].r) { tree[id].col = col;return;}cal(id);int mid = (tree[id].l + tree[id].r)/2;if(r <= mid)update(l,r,id<<1,col);else if(l > mid)update(l,r,id<<1|1,col);else {update(l,mid,id<<1,col);update(mid+1,r,id<<1|1,col);}}void query(int l,int r,int id) {if(tree[id].col > -1) {for(int i=tree[id].l;i<=tree[id].r;i++)color[i] = tree[id].col;return;}if(tree[id].l == tree[id].r)return;int mid = (tree[id].l + tree[id].r)/2;if(r <= mid)query(l,r,id<<1);else if(l > mid)query(l,r,id<<1|1);else {query(l,mid,id<<1);query(mid+1,r,id<<1|1);}}int main() {int n;while(scanf("%d",&n) == 1) {int q = n;init();build(1,N,1);int x,y,c;while(q--) {scanf("%d %d %d",&x,&y,&c);x++;update(x,y,1,c);}query(1,N,1);for(int i=1;i<N;i++)if(color[i - 1] != color[i])if(color[i] > -1)ans[color[i]]++;for(int i=0;i<N;i++)if(ans[i])printf("%d %d\n",i,ans[i]);puts("");}return 0;}