原题地址
没仔细看题目。以为一个人只能选一次。。这样的话用线段树搞一下就可以,求出每个信号要抹去的最小代价,然后一个01背包就可以求出答案啦。
#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
const int N = 1e5+5;
#define lson rt<<1, l, mid
#define rson rt<<1|1, mid+1, r
LL a[N], Min[N<<2], sum, n, m, k, w[N];
LL dp[505];
void update(int rt, int l, int r, int L, int R, LL x) {
if(l > R || L > r) return ;
if(L <= l && R >= r) {
Min[rt] = min(Min[rt], x);
return ;
}
int mid = (l + r) / 2;
update(lson, L, R, x);
update(rson, L, R, x);
}
LL query(int rt, int l, int r, int pos) {
if(l == r) return Min[rt];
int mid = (l + r) / 2;
if(pos <= mid) return min(Min[rt], query(lson, pos));
else return min(Min[rt], query(rson, pos));
}
int main() {
memset(Min, 0x3f, sizeof(Min));
cin >> n >> k >> m;
for (int i = 1; i <= n; i++) {
cin >> a[i];
sum += a[i];
}
int l, r;
LL x;
for (int i = 1; i <= m; i++) {
cin >> l >> r >>x;
update(1,1,n,l,r,x);
}
for (int i = 1; i <= n; i++) {
w[i] = query(1,1,n,i);
}
for (int i = 1; i <= n; i++) {
if(a[i] >= 0) continue;
a[i] = -a[i];
for (int j = k; j >= w[i]; j--) {
dp[j] = max(dp[j], dp[j-w[i]]+a[i]);
}
}
cout << sum + dp[k] << endl;
}