FZU 2079 最大获利（线段树+DP）

#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <cmath>
#include <vector>
#include <queue>
#include <map>
#include <set>
#include <stack>
#include <algorithm>
using namespace std;

typedef long long LL;
const int N = 200010;
const int inf = 1e9+7;
const double PI = acos(-1.0);
const double eps = 1e-6 ;

#define root 1,n,1
#define lson l,mid,rt<<1
#define rson mid+1,r,rt<<1|1
#define lr rt<<1
#define rr rt<<1|1

int n , m ;
struct node {
    int l , r , w ;
    bool operator < ( const node &a ) const {
        if( r != a.r ) return r < a.r ;
        else return l > a.l ;
    }
}e[N];

LL dp[N] , cost[N] ;

void init(){
    memset( dp , 0 , sizeof dp );
}

LL date[N<<2] ,lazy[N<<2];

void build( int l , int r , int rt ) {
    date[rt] = lazy[rt] = 0 ;
    if( l == r ) return ;
    int mid = ( l + r ) >> 1 ;
    build(lson); build(rson);
}

void Down( int l , int r , int rt ) {
    if( l == r ) return  ;
    if( lazy[rt] != 0 ) {
        date[lr]+= lazy[rt] , lazy[lr] += lazy[rt];
        date[rr]+= lazy[rt] , lazy[rr] += lazy[rt];
        lazy[rt] = 0 ;
    }
}

void Up( int rt ) { date[rt] = max( date[lr] , date[rr] ); }

void update( int l , int r , int rt , int L , int R , LL val) {

    if( L == l && r == R ) {
        date[rt] += val , lazy[rt] += val ; return ;
    }
    Down(l,r,rt);
    int mid = (l+r) >> 1;
    if( R <= mid ) update(lson,L,R,val);
    else if( L > mid ) update(rson,L,R,val);
    else update(lson,L,mid,val) , update(rson,mid+1,R,val);
    Up(rt);
}

LL query( int l , int r , int rt , int L , int R ) {

    if( L == l && r == R ) {
        return date[rt];
    }
    Down(l,r,rt);
    int mid = (l+r)>>1;
    if( R <= mid ) return query(lson,L,R);
    else if( L > mid ) return query(rson,L,R);
    else return max( query(lson,L,mid),query(rson,mid+1,R) );
}

void run () {
    init() ;
    build(root);
    for( int i = 1 ; i <= n ; ++i ){
        scanf("%I64d",&cost[i]) ;
    }
    for( int i = 0 ; i < m ; ++i ) {
        scanf("%d%d%d",&e[i].l,&e[i].r,&e[i].w);
    }
    sort( e , e + m );
    int head = 0 ;
    for( int i = 1 ; i <= n ; ++i ) {
        update( root , i  , i  , dp[i-1] );
        update( root , 1 , i , -cost[i] );
        while( head < m && e[head].r <= i )
            update( root , 1 , e[head].l , e[head].w ) , head++ ;
        dp[i] = max( dp[i-1] , query( root , 1 , i ) );
    }
    printf("%I64d\n",dp[n]);
}
int main()
{
    #ifdef LOCAL
        freopen("in.txt","r",stdin);
    #endif // LOCAL
    ios::sync_with_stdio(false);
    while( ~scanf("%d%d",&n,&m) )run() ;
}