区间计数

两个数列 {An} ， {Bn} ，请求出Ans, Ans定义如下：

Ans:=Σni=1Σnj=i[max{Ai,Ai+1,...,Aj}=max{Bi,Bi+1,...,Bj}] 

注：[ ]内表达式为真，则为1，否则为0.

1≤N≤3.5×1051≤Ai,Bi≤N 

样例解释：

7个区间分别为：（1,4），（1,5），（2,4），（2,5），（3,3），（3,5），（4,5）

Input

第一行一个整数N第二行N个整数Ai第三行N个整数Bi

Output

一行，一个整数Ans

Input示例

51 4 2 3 43 2 2 4 1

Output示例

7

#include <iostream>#include <stack>#include <stdio.h>using namespace std;typedef long long int ll;const int MAXN = 350005;int a[MAXN];int b[MAXN];int n;struct node{    node()    {        val = 0;        num = 0;    }        node(int v, int n)    {        val = v;        num = n;    }    int val;    int num;};node prevMax[MAXN];int bufA[MAXN];int bufB[MAXN];int find(int *p, int *q, int pos, int k){    int left = 0;    int right = pos;    int result = -1;        while (left < right-1)    {        int mid = left + (right-left)/2;        if (p[q[mid]] <= k)        {            right = mid;        }        else        {            left = mid;        }    }        if (p[q[right]] > k)    {        result = right;    }    else if (p[q[left]] > k)    {        result = left;    }        return result;}int main(){    cin >> n;     ll result = 0;    for (int i = 0; i < n; i++)    {        cin >> a[i];    }        for (int i = 0; i < n; i++)    {        cin >> b[i];    }        ll sum = 0;    int p = -1;    int q = -1;    int r = -1;        for (int i = 0; i < n; i++)    {        int maxInput = max(a[i], b[i]);        while ((r >= 0) && (maxInput >= prevMax[r].val))        {            sum -= prevMax[r].num;            r--;        }             if ((p >= 0) && a[i] >= a[bufA[p]])        {            p = find(a, bufA, p, a[i]);        }        p++;        bufA[p] = i;                if ((q >= 0) && b[i] >= b[bufB[q]])        {            q = find(b, bufB, q, b[i]);        }        q++;        bufB[q] = i;                bool equal = false;        if (a[i] > b[i])        {            q = find(b, bufB, q, a[i]);            if (b[bufB[q+1]] == a[i])            {                q++;                equal = true;            }        }        else if (a[i] < b[i])        {            p = find(a, bufA, p, b[i]);            if (a[bufA[p+1]] == b[i])            {                p++;                equal = true;            }        }        else        {        equal = true;        }                if (equal)        {            int rightA = bufA[p];            int rightB = bufB[q];                        int right = min(rightA, rightB);            int value = a[bufA[p]];                        int leftA = (p == 0)? -1 : bufA[p-1];            int leftB = (q == 0)? -1 : bufB[q-1];            int left = max(leftA, leftB);                        int num = (right-left);            sum += num;                        r++;            prevMax[r] = node(value, num);        }                result += sum;    }        cout << result << endl;    return 0;}