[洛谷P1901]发射站

原题传送门

这道题跟[NOIP2012]开车旅行的预处理完全一样。通过链表来实现。

#include <bits/stdc++.h>

using namespace std;

#define re register
#define rep(i, a, b) for (re int i = a; i <= b; ++i)
#define repd(i, a, b) for (re int i = a; i >= b; --i)
#define maxx(a, b) a = max(a, b);
#define minn(a, b) a = min(a, b);
#define LL long long
#define inf (1 << 30)

const int maxn = 1e6 + 5;

inline int read() {
    int w = 0, f = 1; char c = getchar();
    while (!isdigit(c)) f = c == '-' ? -1 : f, c = getchar();
    while (isdigit(c)) w = (w << 3) + (w << 1) + (c ^ '0'), c = getchar();
    return w * f;
}

struct Tower {
    int H, n;
} a[maxn];
bool cmp(Tower a, Tower b) {
    return a.H < b.H;
}

int n, L[maxn], R[maxn], V[maxn], ans[maxn];

int main() {
    n = read();

    rep(i, 1, n) a[i].n = i, L[i] = i-1, R[i] = i+1, a[i].H = read(), V[i] = read();

    sort(a + 1, a + n + 1, cmp);

    rep(i, 1, n) {
        ans[L[a[i].n]] += V[a[i].n];
        ans[R[a[i].n]] += V[a[i].n];
        R[L[a[i].n]] = R[a[i].n];
        L[R[a[i].n]] = L[a[i].n];
    }
    int res = 0;
    rep(i, 1, n) maxx(res, ans[i]);
    printf("%d", res);

    return 0;
}

 这道题还有更加简单的方法，就是维护一个栈。写法比上面的要短。这里就不放了。