一、题目分析
此题本质是计算 ( W ⋅ ( Q × K T ) ) × V (W·(Q×K^T))×V (W⋅(Q×KT))×V的值。
注意任务要求:
70% 的测试数据满足:n<=100且d<=10 。输入矩阵、向量中的元素均为整数,且绝对值均不超过30 。
全部的测试数据满足:n<=10^4 且d<=20 。输入矩阵、向量中的元素均为整数,且绝对值均不超过 1000;
因此如果按照顺序计算,那么运算量超过10^9(约为1s),则会超时,因此可以在计算中合并一些运算。
二、代码展示(c)
#include <malloc.h>
int main() {int n,d;int i,j;scanf("%d%d",&n,&d);//printf("%d %d\n",n,d);//-------------------初始化-----------------------int** Q = (int**)malloc(sizeof(int*) * n);int** K = (int**)malloc(sizeof(int*) * n);int** V = (int**)malloc(sizeof(int*) * n);int* W = (int*)malloc(sizeof(int*) * n);//-------------------初始化-----------------------for(i = 0;i < n;i++){*(Q+i) = (int*)malloc(sizeof(int) * d);for(j = 0;j < d;j++){scanf("%d",&Q[i][j]);}}for(i = 0;i < n;i++){*(K+i) = (int*)malloc(sizeof(int) * d);for(j = 0;j < d;j++){scanf("%d",&K[i][j]);}}for(i = 0;i < n;i++){*(V+i) = (int*)malloc(sizeof(int) * d);for(j = 0;j < d;j++){scanf("%d",&V[i][j]);}}long long** res = (long long**)malloc(sizeof(long long*) * n);//long long** result = (long long**)malloc(sizeof(long long*) * n);for(i = 0;i < n;i++) {*(res+i) = (long long*)malloc(sizeof(long long) * n);//*(result+i) = (long long*)malloc(sizeof(long long) * d);scanf("%d",&W[i]);}for (i = 0;i < n;i++){for(j = 0;j < n;j++){res[i][j] = 0;int k,p;for(k = 0;k < d;k++) {//printf("%d %d\n",Q[i][k],K[j][k]);res[i][j] += (long long)Q[i][k]*(long long)K[j][k];}}for(j = 0;j < d;j++){long long result = 0;int k,p;for(k = 0;k < n;k++) {result += (long long)res[i][k]*(long long)V[k][j]*(long long)W[i];}printf("%lld ",result);}printf("\n");}return 0;
}
三、注意事项
此题因为存入的数很多,因此需要动态开辟二维数组。设一个二维数组为Q,方式如下:
int** Q = (int**)malloc(sizeof(int*) * n);
for(i = 0;i < n;i++){*(Q+i) = (int*)malloc(sizeof(int) * d);for(j = 0;j < d;j++){scanf("%d",&Q[i][j]);}}
边创建数组边读入会更省时间~