Ural_1019. Line Painting(线段树)

　　/*额滴神啊。。。调了整整一晚上。简单染色问题，染完色后再扫描一遍，找出最大的
连续是白色的序列。开始必须把0, 109 这两个点加上去。就因为这个都快调shi了。。。扫
描的时候用一个数组记录染色后区间的颜色。然后找连续颜色是白色的最大区间。

数据有点大，用离散化吧。*/

//My Code:

#include <iostream>
#include <cstring>
#include <cmath>
#include <cstdio>
#include <map>
#include <queue>
#include <stack>
#include <vector>
#include <string>
#include <algorithm>

#define L(t) t << 1
#define R(t) t << 1 | 1

using namespace std;


const int N = 10007;

struct tree {
    int l, r;
    int col;
} tree[N<<2];

struct axis {
    int s, e;
    int col;
} ax[N];

int p[N], t[N], T, col[N];

int get_pos(int x) {
    int l = 0, r = T, mid;
    while(l <= r) {
        mid = (l + r) >> 1;
        if(p[mid] == x)    return mid;
        else if(p[mid] > x)    r = mid -1;
        else    l = mid + 1;
    }
}

void creat(int t, int l, int r) {
    tree[t].l = l;
    tree[t].r = r;
    tree[t].col = 1;
    if(l + 1 == r)    return ;
    int mid = (l + r) >> 1;
    creat(L(t), l, mid);
    creat(R(t), mid, r);
}

void updata(int t, int l, int r, int col) {
    if(tree[t].l >= l && tree[t].r <= r) {
        //printf("%d %d %d\n", tree[t].l, tree[t].r, col);
        tree[t].col = col;
        return ;
    }
    if(tree[t].col >= 0 && tree[t].col != col) {
        tree[L(t)].col = tree[R(t)].col = tree[t].col;
        tree[t].col = -1;
    }
    int mid = (tree[t].l + tree[t].r) >> 1;
    if(l >= mid)    updata(R(t), l, r, col);
    else if(r <= mid)    updata(L(t), l, r, col);
    else {
        updata(L(t), l, mid, col);
        updata(R(t), mid, r, col);
    }
}

void query(int t, int l, int r) {
    //printf("%d\n", tree[t].col);
    if(tree[t].col >= 0) {
        //printf("%d %d %d\n", tree[t].l, tree[t].r, tree[t].col);
        for(int i = tree[t].l; i < tree[t].r; i++) {
            col[i] = tree[t].col;
        }
        return ;
    }
    int mid = (tree[t].l + tree[t].r) >> 1;
    if(l >= mid)    query(R(t), l, r);
    else if(r <= mid)    query(L(t), l, r);
    else {
        query(L(t), l, mid);
        query(R(t), mid, r);
    }
}

int main() {
    //freopen("data.in", "r", stdin);

    int n, i, tmp, x, y;
    char c;
    while(~scanf("%d", &n)) {
        memset(col, 1, sizeof(col));
        memset(t, 0, sizeof(t));
        memset(p, 0, sizeof(p));
        memset(tree, 0, sizeof(tree));

        ax[0].s = 0; ax[0].e = 1e9; ax[0].col = 1;
        T = 0; t[T++] = 0; t[T++] = 1e9;
        for(i = 1; i <= n; i++) {
            scanf("%d%d %c", &ax[i].s, &ax[i].e, &c);
            if(c == 'w')    ax[i].col = 1;
            else    ax[i].col = 0;
            t[T++] = ax[i].s;
            t[T++] = ax[i].e;
        }
        sort(t, t+T+1);
        tmp = t[0]; T = 0; p[T++] = tmp;
        for(i = 1; i <= n+n+2; i++) {
            //printf("%d ", t[i]);
            if(tmp != t[i]) {
                tmp = t[i];
                p[T++] = tmp;
            }
        }
        //cout << endl;
        
        /*for(i = 0; i <= T; i++) {
            printf("%d ", p[i]);
        }
        cout << endl;*/
        T--; creat(1, 0, T);
        for(i = 0; i <= n; i++) {
            x = get_pos(ax[i].s);
            y = get_pos(ax[i].e);
            //printf("%d %d %d %d %d\n", ax[i].s, ax[i].e, x, y, ax[i].col);
            updata(1, x, y, ax[i].col);
        }
        query(1, 0, T);
        int s = 0, e = 0, ts, te;
        for(i = 0; i <= T; i++) {
            ts = p[i];
            while(col[i] == 1)    i++;
            te = p[i];
            if(te - ts > e - s) {
                e = te; s = ts;
            }
        }
        printf("%d %d\n", s, e);
    }
    return 0;
}