POJ 2777 Count Color（线段树）

POJ 2777 Count Color

题目链接

就一个线段树，颜色二进制表示就可以，成段更新成段查询延迟操作

代码：

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

#define lson(x) ((x<<1)+1)
#define rson(x) ((x<<1)+2)

const int N = 100005;

struct Node {
int l, r, color, lazy;
} node[N * 4];

void pushup(int x) {
node[x].color = node[lson(x)].color | node[rson(x)].color;
}

void pushdown(int x) {
if (node[x].lazy) {
node[lson(x)].color = node[x].lazy; node[lson(x)].lazy = node[x].lazy;
node[rson(x)].color = node[x].lazy; node[rson(x)].lazy = node[x].lazy;
node[x].lazy = 0;
}
}

void build(int l, int r, int x = 0) {
node[x].l = l; node[x].r = r; node[x].lazy = 0;
if (l == r) {
node[x].color = 1;
return;
}
int mid = (l + r) / 2;
build(l, mid, lson(x));
build(mid + 1, r, rson(x));
pushup(x);
}

void add(int l, int r, int c, int x = 0) {
if (node[x].l >= l && node[x].r <= r) {
node[x].color = (1<<(c - 1));
node[x].lazy = (1<<(c - 1));
return;
}
pushdown(x);
int mid = (node[x].l + node[x].r) / 2;
if (l <= mid) add(l, r, c, lson(x));
if (r > mid) add(l, r, c, rson(x));
pushup(x);
}

int query(int l, int r, int x = 0) {
if (node[x].l >= l && node[x].r <= r)
return node[x].color;
int mid = (node[x].l + node[x].r) / 2;
int ans = 0;
pushdown(x);
if (l <= mid) ans |= query(l, r, lson(x));
if (r > mid) ans |= query(l, r, rson(x));
pushup(x);
return ans;
}

int bitcount(int x) {
return x == 0 ? 0 : bitcount(x>>1) + (x&1);
}

int l, t, o;
char str[5];
int a, b, v;

int main() {
while (~scanf("%d%d%d", &l, &t, &o)) {
build(1, l);
while (o--) {
scanf("%s%d%d", str, &a, &b);
if (a > b) swap(a, b);
if (str[0] == 'C') {
scanf("%d", &v);
add(a, b, v);
} else printf("%d\n", bitcount(query(a, b)));
}
}
return 0;
}