1 条题解

  • -1
    @ 2022-7-12 23:04:55
    #include <iostream>
    #include <cstdio>
    #include <algorithm>
    #include <cstring>
    #include <cmath>
    
    using namespace std;
    
    const int MAXN = 85, Mod = 10000; //高精四位压缩大法好 
    int n, m;
    int ar[MAXN];
    
    struct HP {
    	int p[505], len;
    	HP() {
    		memset(p, 0, sizeof p);
    		len = 0;
    	} //这是构造函数,用于直接创建一个高精度变量 
    	void print() {
    		printf("%d", p[len]);  
            for (int i = len - 1; i > 0; i--) {  
                if (p[i] == 0) {
    				printf("0000"); 
    				continue;
    			}
                for (int k = 10; k * p[i] < Mod; k *= 10) 
    				printf("0");
                printf("%d", p[i]);
            }
    	} //四位压缩的输出 
    } f[MAXN][MAXN], base[MAXN], ans;
    
    HP operator + (const HP &a, const HP &b) {
    	HP c; c.len = max(a.len, b.len); int x = 0;
    	for (int i = 1; i <= c.len; i++) {
    		c.p[i] = a.p[i] + b.p[i] + x;
    		x = c.p[i] / Mod;
    		c.p[i] %= Mod;
    	}
    	if (x > 0)
    		c.p[++c.len] = x;
    	return c;
    } //高精+高精 
    
    HP operator * (const HP &a, const int &b) {
    	HP c; c.len = a.len; int x = 0;
    	for (int i = 1; i <= c.len; i++) {
    		c.p[i] = a.p[i] * b + x;
    		x = c.p[i] / Mod;
    		c.p[i] %= Mod;
    	}
    	while (x > 0)
    		c.p[++c.len] = x % Mod, x /= Mod;
    	return c;
    } //高精*单精 
    
    HP max(const HP &a, const HP &b) {
    	if (a.len > b.len)
    		return a;
    	else if (a.len < b.len)
    		return b;
    	for (int i = a.len; i > 0; i--)
    		if (a.p[i] > b.p[i])
    			return a;
    		else if (a.p[i] < b.p[i])
    			return b;
    	return a;
    } //比较取最大值 
    
    void BaseTwo() {
    	base[0].p[1] = 1, base[0].len = 1;
    	for (int i = 1; i <= m + 2; i++){ //这里是m! m! m! 我TM写成n调了n年... 
    		base[i] = base[i - 1] * 2;
    	}
    } //预处理出2的幂 
    
    int main(void) {
    	scanf("%d%d", &n, &m);
    	BaseTwo();
    	while (n--) {
    		memset(f, 0, sizeof f);
    		for (int i = 1; i <= m; i++)
    			scanf("%d", &ar[i]);
    		for (int i = 1; i <= m; i++)
    			for (int j = m; j >= i; j--) { //因为终值是小区间,DP自然就从大区间开始 
    				f[i][j] = max(f[i][j], f[i - 1][j] + base[m - j + i - 1] * ar[i - 1]); 
    				f[i][j] = max(f[i][j], f[i][j + 1] + base[m - j + i - 1] * ar[j + 1]);
    			} //用结构体重载运算符写起来比较自然 
    		HP Max;
    		for (int i = 1; i <= m; i++)
    			Max = max(Max, f[i][i] + base[m] * ar[i]);
    		ans = ans + Max; //记录到总答案中 
    	}
    	ans.print(); //输出 
    	return 0;
    }
    
    • 1

    信息

    ID
    6
    时间
    1000ms
    内存
    125MiB
    难度
    5
    标签
    递交数
    26
    已通过
    21
    上传者