问题描述

Solution

Code

// 单调栈
#pragma GCC target("avx,sse2,sse3,sse4,popcnt")
#pragma GCC optimize("O2,O3,Ofast,inline,unroll-all-loops,-ffast-math")
#include <bits/stdc++.h>
using namespace std;
#define js ios::sync_with_stdio(false);cin.tie(0); cout.tie(0)
#define all(__vv__) (__vv__).begin(), (__vv__).end()
#define endl "\n"
#define pai pair<int, int>
#define mk(__x__,__y__) make_pair(__x__,__y__)
#define ms(__x__,__val__) memset(__x__, __val__, sizeof(__x__))
typedef long long ll; typedef unsigned long long ull; typedef long double ld;
inline ll read() { ll s = 0, w = 1; char ch = getchar(); for (; !isdigit(ch); ch = getchar()) if (ch == '-') w = -1; for (; isdigit(ch); ch = getchar())    s = (s << 1) + (s << 3) + (ch ^ 48); return s * w; }
inline void print(ll x) { if (!x) { putchar('0'); return; } char F[40]; ll tmp = x > 0 ? x : -x; if (x < 0)putchar('-');    int cnt = 0;    while (tmp > 0) { F[cnt++] = tmp % 10 + '0';        tmp /= 10; }    while (cnt > 0)putchar(F[--cnt]); }
inline ll gcd(ll x, ll y) { return y ? gcd(y, x % y) : x; }
ll qpow(ll a, ll b) { ll ans = 1;    while (b) { if (b & 1)    ans *= a;        b >>= 1;        a *= a; }    return ans; }    ll qpow(ll a, ll b, ll mod) { ll ans = 1; while (b) { if (b & 1)(ans *= a) %= mod; b >>= 1; (a *= a) %= mod; }return ans % mod; }
inline int lowbit(int x) { return x & (-x); }
const int dir[][2] = { {0,1},{1,0},{0,-1},{-1,0},{1,1},{1,-1},{-1,1},{-1,-1} };
const int MOD = 1e9 + 7;
const int INF = 0x3f3f3f3f;

const int N = 1e6 + 7;
ll st[N], top;
ll a[N], h[N], w[N];
ll ans;

int main() {
    int n = read();
    for (int i = 1; i <= n; ++i)    a[i] = read(); //起始宽度
    for (int i = 1; i <= n; ++i)    h[i] = read();
    h[n + 1] = top = 0;    //增加哨兵防止留下矩阵未出栈
    ans = 0;
    for (int i = 1; i <= n + 1; ++i) {
        if (h[i] > st[top])
            st[++top] = h[i], w[top] = a[i]; //w[]表示栈中当前矩阵宽度
        else {
            ll with = 0;
            while (top and st[top] >= h[i]) { //h[0]=0
                with += w[top];
                ans = max(ans, with * st[top]);
                --top;
            }
            st[++top] = h[i], w[top] = with + a[i];
        }
    }
    print(ans);
    return 0;
}