poj2777

         线段树直接处理，lazy标记记得下放。每个区间的各种颜色可以用二进制保存，因为最多只有30种颜色，所以用int就行。

      两个区间合并后的颜色用或运算。

AC代码：

#include<cstdio>
#include<algorithm>
using namespace std;
const int maxn = 4e5 + 5;
struct node{
    int L, R;
    int color, tag;
}t[maxn];

void Build(int l, int r, int cur){ //Build the tree
    t[cur].L = l; t[cur].R = r;
    t[cur].color = t[cur].tag = 1;
    if(l == r) return;
    int mid = (l + r) / 2;
    Build(l, mid, cur << 1);
    Build(mid + 1, r, (cur << 1) + 1);
}

void Update(int l, int r, int c, int cur){
    //printf("%d %d\n",l,r);
    int l1 = t[cur].L, r1 = t[cur].R;
    if(l1 == l && r1 == r){
        t[cur].color = 1 << (c - 1);
        t[cur].tag = 1;
        return;
    }
    if(t[cur].tag){ //Let the lazy tag down
        t[(cur << 1) + 1].tag = t[cur << 1].tag = t[cur].tag;
        t[(cur << 1) + 1].color = t[cur << 1].color = t[cur].color;
    }

    int mid = (l1 + r1) / 2;
    if(r <= mid) Update(l, r, c, cur << 1);
    else if(l >= mid + 1) Update(l, r, c, (cur << 1) + 1);
    else {
        Update(l, mid, c, cur << 1);
        Update(mid + 1, r, c, (cur << 1) + 1);
    }

    t[cur].color = t[cur << 1].color | t[(cur << 1) + 1].color;
    int x = t[cur].color;
    t[cur].tag = (x & (x - 1)) ? 0 :1;
}

int Find(int l, int r, int cur){
    int l1 = t[cur].L, r1 = t[cur].R;
    if(l1 == l && r1 == r || t[cur].tag) return t[cur].color;

    if(t[cur].tag){ //Let the lazy tag down
        t[(cur << 1) + 1].tag = t[cur << 1].tag = t[cur].tag;
        t[(cur << 1) + 1].color = t[cur << 1].color = t[cur].color;
    }

    int mid = (l1 + r1) / 2;
    if(r <= mid) return Find(l, r, cur << 1);
    else if(l >= mid + 1) return Find(l, r, (cur << 1) + 1);
    else {
        int x = Find(l, mid, cur << 1);
        int y = Find(mid + 1, r, (cur << 1) + 1);
        return x | y;
    }
}
int main(){
    int L, T, Q;
    while(scanf("%d%d%d", &L, &T, &Q) == 3){
        Build(1, L, 1);
        getchar();
        char ch;
        int a, b, c;
        for(int i = 0; i < Q; ++i){
            scanf("%c",&ch);
            if(ch == 'C') {
                scanf("%d%d%d", &a, &b, &c);
                if(a > b) swap(a, b);
                Update(a, b, c, 1);
            }
            else {
                scanf("%d%d", &a, &b);
                if(a > b) swap(a, b);
                int x = Find(a, b, 1);
                int ans = 0;
                while(x > 0){
                    if(x & 1) ++ans;
                    x >>= 1;
                }
                printf("%d\n", ans);
            }
            getchar();
        }
    }
    return 0;
}

如有不当之处欢迎指出！

转载于:https://www.cnblogs.com/flyawayl/p/8305464.html