UVa 11997 K Smallest Sums/priority queue

Priority queue

n rows n digits per row Select a sum sum the smallest n

Suppose only 2 rows

Sort each line first

A1 A2 A3 ... an

B1 b2 b3 ... Bn

Put A1 + B1, A2 + b1, A3 + B1,..., an + B1 into the queue

Then take out a minimum (pop) if it is ax + by then put in a ax+b (y+1) (push) until the n is removed and they are stored in array c

Now there are n so can 22 merge the first and second rows merge the results in the third row and merge ....

#include <cstdio> #include <queue> #include <cstring> #include <algorithm> const int MAXN = 800;

using namespace Std;
int A[MAXN][MAXN];
	struct Item {int s; 
	int b;
	Item (int s, int b): s (s), B (b) {} BOOL operator < (const item& RHS) Const {return s > rhs.s;
}	
};

int n;
	 void merge (int* A, int* B, int* C) {priority_queue <Item> q;
	 for (int i = 0; i < n; i++) Q.push (Item (a[i]+b[0], 0));
	 	for (int i = 0; i < n; i++) {Item item = Q.top ();
	 	Q.pop ();
	 	C[i] = ITEM.S;
	 	int b = ITEM.B; 
	 if (B+1 < n) q.push (Item (item.s-b[b]+b[b+1], b+1)); 
	}} int main () {int i, J; while (scanf ("%d", &n) = = 1) {for (i = 0; i < n; i++) {for (j = 0; J < N; j + +) scanf ("%d", &a[i][
			J]);
		Sort (A[i], a[i]+n);
		} for (i = 1; i < n; i++) merge (A[0], a[i], a[0]);
		printf ("%d", a[0][0]); 
		for (i = 1; i < n; i++) printf ("%d", a[0][i]);
	printf ("\ n");
} return 0; }