Poj 3225 help with intervals (line segment tree)

Link: poj 3225 help with intervals

Simulate the set operation and output the final set.

Solution: Line Segment tree.

• U l r: [L, R] is set to 1.
• I l r: [0, L), (R, maxn] is set to 0
• D l r: [L, R] is set to 0.
• C l r: [0, L), set (R, maxn] to 0, and set [L, R] to inverse.
• S l r: returns the inverse of the range [L, R.

Then, pay attention to the section opening and closing of the line tree of basic water.

#include <cstdio>#include <cstring>#include <algorithm>using namespace std;const int maxn = 65535 * 2;#define lson(x) ((x)<<1)#define rson(x) (((x)<<1)+1)int lc[maxn * 4], rc[maxn * 4], set[maxn * 4], filp[maxn * 4];inline void splay(int u) {    filp[u] ^= 1;    if (filp[u] && set[u] != -1) {        filp[u] = 0;        set[u] ^= 1;    }}inline void maintain(int u, int v) {    set[u] = v;    filp[u] = 0;}inline void pushdown (int u) {    if (set[u] != -1) {        maintain(lson(u), set[u]);        maintain(rson(u), set[u]);        set[u] = -1;    }    if (filp[u]) {        splay(lson(u));        splay(rson(u));        filp[u] = 0;    }}void build (int u, int l, int r) {    lc[u] = l;    rc[u] = r;    maintain(u, -1);    if (l == r) {        maintain(u, 0);        return;    }    int mid = (l + r) / 2;    build (lson(u), l, mid);    build (rson(u), mid + 1, r);}void modify (int u, int l, int r, int v) {    if (l > r) return;    if (l <= lc[u] && rc[u] <= r) {        maintain(u, v);        return;    }    pushdown(u);    int mid = (lc[u] + rc[u]) / 2;    if (l <= mid)        modify(lson(u), l, r, v);    if (r > mid)        modify(rson(u), l, r, v);}void change (int u, int l, int r) {    if (l > r) return;    if (l <= lc[u] && rc[u] <= r) {        splay(u);        return;    }    pushdown(u);    int mid = (lc[u] + rc[u]) / 2;    if (l <= mid)        change(lson(u), l, r);    if (r > mid)        change(rson(u), l, r);}int query (int u, int x) {    if (lc[u] == x && x == rc[u])        return set[u];    pushdown(u);    int mid = (lc[u] + rc[u]) / 2;    if (x <= mid)        return query(lson(u), x);    else        return query(rson(u), x);}int L, R;char op, LP, RP;inline void put (int left, int right) {    if (left&1)        printf("(%d,", left/2);    else        printf("[%d,", left/2);    if (right&1)        printf("%d)", (right + 1) / 2);    else        printf("%d]", right / 2);}int main () {    build (1, 0, maxn);    while (~scanf("%c%*c%c%d,%d%c%*c", &op, &LP, &L, &R, &RP)) {        L *= 2;        R *= 2;        if (LP == ‘(‘)            L++;        if (RP == ‘)‘)            R--;        if (op == ‘U‘) {            modify(1, L, R, 1);        } else if (op == ‘I‘) {            modify(1, 0, L - 1, 0);            modify(1, R + 1, maxn, 0);        } else if (op == ‘D‘) {            modify(1, L, R, 0);        } else if (op == ‘C‘) {            change(1, L, R);            modify(1, 0, L - 1, 0);            modify(1, R + 1, maxn, 0);        } else if (op == ‘S‘)            change(1, L, R);    }    bool flag = false;    int c = 0, t;    for (int i = 0; i <= maxn; i++) {        int s = query(1, i);        if (s && !flag) {            t = i;            flag = true;        } else if (!s && flag) {            if (c++)                printf(" ");            put(t, i-1);            flag = false;        }    }    if (c == 0)        printf("empty set\n");    else        printf("\n");    return 0;}

Poj 3225 help with intervals (line segment tree)