【Codeforces 915E】 Physical Education Lessons

【题目链接】

点击打开链接

【算法】

线段树，注意数据量大，要动态开点

【代码】

#include<bits/stdc++.h>
using namespace std;
const int MAXN = ;

int n,q,l,r,opt,size = ,root = ;
struct Node {
        int lc,rc,tag,sum;
} Tree[MAXN];

template <typename T> inline void read(T &x) {
        int f = ; x = ;
        char c = getchar();
        for (; !isdigit(c); c = getchar()) { if (c == '-') f = -f; }
        for (; isdigit(c); c = getchar()) x = (x << ) + (x << ) + c - '';
        x *= f;
}
template <typename T> inline void write(T x) {
    if (x < ) { putchar('-'); x = -x; }
    if (x > ) write(x/);
    putchar(x%+'');
}
template <typename T> inline void writeln(T x) {
    write(x);
    puts("");
}

inline void push_up(int root) {
        Tree[root].sum = Tree[Tree[root].lc].sum + Tree[Tree[root].rc].sum;
}
inline void push_down(int l,int r,int root) {
        int mid = (l + r) >> ;
        if (Tree[root].tag != -) {
                if (!Tree[root].lc) Tree[root].lc = ++size;
                if (!Tree[root].rc) Tree[root].rc = ++size;
                Tree[Tree[root].lc].tag = Tree[Tree[root].rc].tag = Tree[root].tag;
                Tree[Tree[root].lc].sum = Tree[root].tag * (mid - l + );
                Tree[Tree[root].rc].sum = Tree[root].tag * (r - mid);
                Tree[root].tag = -;
        }
}
inline void modify(int &root,int l,int r,int ql,int qr,int val) {
        int mid;
        if (!root) root = ++size;
        if (l == ql && r == qr) {
                Tree[root].sum = val * (r - l + );
                Tree[root].tag = val;
                return;
        }
        push_down(l,r,root);
        mid = (l + r) >> ;
        if (mid >= qr) modify(Tree[root].lc,l,mid,ql,qr,val);
        else if (mid +  <= ql) modify(Tree[root].rc,mid+,r,ql,qr,val);
        else {
                modify(Tree[root].lc,l,mid,ql,mid,val);
                modify(Tree[root].rc,mid+,r,mid+,qr,val);
        }
        push_up(root);
}

int main() {

        read(n); read(q);
        while (q--) {
                read(l); read(r); read(opt);
                if (opt == ) modify(root,,n,l,r,);
                else modify(root,,n,l,r,);
                writeln(n - Tree[].sum);
        } 

        return ;

}