BZOJ 1941: [Sdoi2010]Hide and Seek(k-d Tree)

#include<cstdio>
#include<algorithm>
//#define int long long 
//#define getchar() (p1 == p2 && (p2 = (p1 = buf) + fread(buf, 1, 1 << 21, stdin), p1 == p2) ? EOF : *p1++)
using namespace std;
const int MAXN = 200001, INF = 1e9 + 10;
char buf[1 << 21], *p1 = buf, *p2 = buf;
inline int read() {
    char c = getchar(); int x = 0, f = 1;
    while(c < ‘0‘ || c > ‘9‘) {if(c == ‘-‘) f = -1; c = getchar();}
    while(c >= ‘0‘ && c <= ‘9‘) x = x * 10 + c - ‘0‘, c = getchar();
    return x * f;
}
int N;
int WD = 0, cur = 0, root;
#define ls(k) T[k].ls
#define rs(k) T[k].rs
struct Point {
    int x[2];
    bool operator < (const Point &rhs) const {
        return x[WD] < rhs.x[WD];
    }
}p[MAXN];
struct Node {
    int mi[2], mx[2], ls, rs;
    Point tp;
}T[MAXN];
int NewNode() {
    return ++cur;
}
void update(int k) {
    for(int i = 0; i <= 1; i++) {
        T[k].mi[i] = T[k].mx[i] = T[k].tp.x[i];
        if(ls(k)) T[k].mi[i] = min(T[ls(k)].mi[i], T[k].mi[i]), T[k].mx[i] = max(T[k].mx[i], T[ls(k)].mx[i]);
        if(rs(k)) T[k].mi[i] = min(T[rs(k)].mi[i], T[k].mi[i]), T[k].mx[i] = max(T[k].mx[i], T[rs(k)].mx[i]);
    }
}
int Build(int l, int r, int wd) {
    if(l > r) return 0;
    int k = NewNode(), mid = l + r >> 1;
    WD = wd;
    nth_element(p + l, p + mid, p + r + 1);
    T[k].tp = p[mid];
    T[k].ls = Build(l, mid - 1, wd ^ 1);
    T[k].rs = Build(mid + 1, r, wd ^ 1);
    update(k);
    return k;
}
int Ans;
int dis(Point a, Point b) {//曼哈顿距离 
    return abs(a.x[0] - b.x[0]) + abs(a.x[1] - b.x[1]);
}
int GetMinDis(Point a, Node b) {// 点到矩阵的最小曼哈顿距离 
    int rt = 0;
    for(int i = 0; i <= 1; i++)     
        rt += max(0, a.x[i] - b.mx[i]) + max(0, b.mi[i] - a.x[i]);
    return rt;
}
int GetMaxDis(Point a, Node b) {//最大曼哈顿距离 
    int rt = 0;
    for(int i = 0; i <= 1; i++)
        rt += max( max(0, a.x[i] - b.mi[i]), max(0, b.mx[i] - a.x[i]) );
        //rt += max(abs(a.x[i] - b.mi[i]), abs(a.x[i] - b.mx[i]));
    return rt;
}
int QueryMax(int k, Point a) {
    Ans = max(Ans, dis(a, T[k].tp));
    int disl = -INF, disr = -INF;
    if(ls(k)) disl = GetMaxDis(a, T[ls(k)]); 
    if(rs(k)) disr = GetMaxDis(a, T[rs(k)]);
    if(disl > disr) {
        if(disl > Ans) Ans = QueryMax(ls(k), a);
        if(disr > Ans) Ans = QueryMax(rs(k), a);
    }
    else {
        if(disr > Ans) Ans = QueryMax(rs(k), a);
        if(disl > Ans) Ans = QueryMax(ls(k), a);
    }
}
int QueryMin(int k, Point a) {
    int tmp = dis(a, T[k].tp);
    if(tmp) Ans = min(Ans, tmp);
    int disl = INF, disr = INF;
    if(ls(k)) disl = GetMinDis(a, T[ls(k)]); 
    if(rs(k)) disr = GetMinDis(a, T[rs(k)]);
    if(disl < disr) {
        if(disl < Ans) Ans = QueryMin(ls(k), a);
        if(disr < Ans) Ans = QueryMin(rs(k), a);
    }
    else {
        if(disr < Ans) Ans = QueryMin(rs(k), a);
        if(disl < Ans) Ans = QueryMin(ls(k), a);
    }
}
main() {
    #ifdef WIN32
    freopen("a.in", "r", stdin);
    #endif
    N = read();
    for(int i = 1; i <= N; i++) p[i].x[0] = read(), p[i].x[1] = read();
    root = Build(1, N, 0);
    int ans = INF, ans1 = 0, ans2 = 0;
    for(int i = 1; i <= N; i++) {
        ans1 = 0, ans2 = 0;
        Ans = -INF; 
        QueryMax(root, p[i]); 
        ans1 = Ans;
        Ans = INF;  
        QueryMin(root, p[i]); 
        ans2 = Ans;
    //    printf("%d %d\n", ans1, ans2);
        ans = min(ans, ans1 - ans2);
    }
    printf("%d", ans);
}