POJ - 2528 - Mayor's posters 【线段树+离散化+补点】

#include <cstdio>
#include <iostream>
#include <set>
#include <cstring>
#include <string>
#define left rt<<1
#define right rt<<1|1
using namespace std;

const int MAXN = 32768 + 5;
int setv[MAXN << 2]; // 很不科学，这里一定要开大一点才AC，按道理说2*MAXN-1的空间就够了的。。。WA到哭泣
int hash[10000005];

struct Interval{
    int l, r;
} a[10005];

bool color[10005];
int ans;

void pushdown(int rt)
{
    if(setv[rt] != -1) {
        setv[left] = setv[right] = setv[rt];
        setv[rt] = -1;
    }    
}

void update(int ql, int qr, int x, int rt, int l, int r)
{
    if(ql <= l && r <= qr) {
        setv[rt] = x;
        return;
    }    
    pushdown(rt);
    int m = (l + r) >> 1;
    if(ql <= m)    update(ql, qr, x, left, l, m);
    if(qr > m)    update(ql, qr, x, right, m+1, r);
}

void query(int ql, int qr, int rt, int l, int r)
{
    if(setv[rt] != -1) {
        if(!color[setv[rt]]) {
            ans++;
            color[setv[rt]] = 1;
        }
        return;
    }
    if(l==r)    return;
    
    pushdown(rt);
    int m = (l + r) >> 1;
    if(ql <= m)    query(ql, qr, left, l, m);
    if(qr > m)    query(ql, qr, right, m+1, r);
}

int main ()
{
    int c, n;
    scanf("%d", &c);
    while(c--) {
        scanf("%d", &n);
        set<int> st;
        for(int i=0; i<n; i++) {
            scanf("%d%d", &a[i].l, &a[i].r);
            st.insert(a[i].l);
            st.insert(a[i].r);
        }
        int pre, tot=0;
        for(set<int>::iterator p=st.begin(); p != st.end(); ++p) {
            if(p==st.begin()) {
                hash[*p] = ++tot;
            } else {
                if(*p - pre == 1) {
                    hash[*p] = ++tot;
                } else {
                    hash[*p - 1] = ++tot;
                    hash[*p] = ++tot;
                }
            }
            pre = *p;
        }
        memset(setv, -1, sizeof(setv));
        memset(color, false, sizeof(color));
        
        for(int i=0; i<n; i++) {
            update(hash[a[i].l], hash[a[i].r], i+1, 1, 1, tot);
        }
        ans = 0;
        query(1, tot, 1, 1, tot);
        printf("%d\n", ans);
    }
    return 0;
}

#include <cstdio>
#include <iostream>
#include <set>
#include <cstring>
#include <string>
#include <algorithm>
#define left rt<<1
#define right rt<<1|1
using namespace std;

const int MAXN = 32768 + 5;
int setv[MAXN << 2];

struct Interval{
    int l, r;
} a[10005];

bool color[10005];
int ans;
int t[10005 * 3];

void pushdown(int rt)
{
    if(setv[rt] != -1) {
        setv[left] = setv[right] = setv[rt];
        setv[rt] = -1;
    }    
}

void update(int ql, int qr, int x, int rt, int l, int r)
{
    if(ql <= l && r <= qr) {
        setv[rt] = x;
        return;
    }    
    pushdown(rt);
    int m = (l + r) >> 1;
    if(ql <= m)    update(ql, qr, x, left, l, m);
    if(qr > m)    update(ql, qr, x, right, m+1, r);
}

void query(int ql, int qr, int rt, int l, int r)
{
    if(setv[rt] != -1) {
        if(!color[setv[rt]]) {
            ans++;
            color[setv[rt]] = 1;
        }
        return;
    }
    if(l==r)    return;
    
    pushdown(rt);
    int m = (l + r) >> 1;
    if(ql <= m)    query(ql, qr, left, l, m);
    if(qr > m)    query(ql, qr, right, m+1, r);
}

int Bin(int key,int n,int X[]) {
    int l = 1,r = n; 
    while (l <= r) { // [l, r]
        int m = (l+r) >> 1;
        if(X[m] == key) return m;
        if(X[m] < key)    l=m+1; 
        else    r=m-1;
    }
    return -1; 
}


int main ()
{
    int c, n;
    scanf("%d", &c);
    while(c--) {
        scanf("%d", &n);
        set<int> st;
        for(int i=0; i<n; i++) {
            scanf("%d%d", &a[i].l, &a[i].r);
            st.insert(a[i].l);
            st.insert(a[i].r);
        }
        memset(setv, -1, sizeof(setv));
        memset(color, false, sizeof(color));

        int tot = 0;
        for(set<int>::iterator p=st.begin(); p != st.end(); ++p) {
            t[++tot] = *p;
        }
        int temp_tot=tot;
        for(int i=2; i<=temp_tot; i++) {
            if(t[i]-t[i-1] > 1)    t[++tot] = t[i]-1;
        }
        sort(t+1, t+tot+1);
        
        for (int i = 0; i < n; i++) {
            int l = Bin(a[i].l , tot , t);
            int r = Bin(a[i].r , tot , t); 
            update(l, r, i, 1, 1, tot);
        }
        ans = 0;
        query(1, tot, 1, 1, tot);
        printf("%d\n", ans);
    }
    return 0;
}