RQNOJ 23 花生采摘 解题报告

　　嗯，我练习了下二叉堆，代码写得挺长的，其实题目比较简单，就是贪心就行……

　　嗯，上代码吧：

#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#define left(i) (((i) << 1) + 1)
#define right(i) (((i) << 1) + 2)
#define parent(i) (((i) - 1) >> 1)
struct node{
	int x, y, v;
}heap[400];
int end;
int n, m;

void insert(int v, int x, int y)
{
	int i = end;
	struct node t = {x, y, v};
	while(i != 0){
		if(heap[parent(i)].v < t.v){
			heap[i] = heap[parent(i)];
		}else{
			break;
		}
		i = parent(i);
	}
	heap[i] = t;
	end++;
}

struct node delete(void)
{
	struct node t = heap[0];
	int i = 0, j;
	--end;
	while(left(i) < end){
		j = left(i);
		if(right(i) < end && heap[right(i)].v > heap[j].v){
			j = right(i);
		}
		if(heap[end].v < heap[j].v){
			heap[i] = heap[j];
		}else{
			break;
		}
		i = j;
	}
	heap[i] = heap[end];
	return t;
}

int getdis(struct node a, struct node b)
{
	return abs(a.x - b.x) + abs(a.y - b.y) + 1;
}

int main(int argc, char **argv)
{
	int i, j, t, s;
	struct node l, p;
	int k;
	scanf("%d%d%d", &n, &m, &k);
	for(i = 1; i <= n; i++){
		for(j = 1; j <= m; j++){
			scanf("%d", &t);
			if(t != 0){
				insert(t, i, j);
			}
		}
	}
	t = s = 0;
	p = delete();
	l.x = l.v = 0;
	l.y = p.y;
	while(t + getdis(l, p) + p.x <= k){
		t += getdis(l, p);
		s += p.v;
		l = p;
		if(end == 0){
			break;
		}
		p = delete();
	}
	printf("%d\n", s);
	return 0;
}