解题笔记 之 1027 简单动态规划

动态规划，和LCS有点近似，但是我用递归加结果记录解掉了，感觉这样更直观 -_____-  (其实是类LCS解法的那个一开始就没去考虑....... 面壁一下  )

 

dp方程见代码，应该写的比较利索了

 

#include 
#include 
#include 

#define INFINITE -9999
#define MINUS 4

int score_board[5][5] = { { 5, -1, -2, -1, -3}, 
                                     {-1,  5, -3, -2, -4}, 
                                     {-2, -3,  5, -2, -2}, 
                                     {-1, -2, -2,  5, -1}, 
                                     {-3, -4, -2, -1, INFINITE}};

int score(int* gen_seq1, int len1, int* gen_seq2, int len2);
void init_memory(int gen1, int gen2);
int max(int a, int b, int c);
int* integer_array(char* gen, int len);

int memory[120][120];

int main(int argc, char** argv) {
    int case_count;
    char gen1[121], gen2[121];
    int len1, len2;

    freopen("in.txt", "r", stdin);
    scanf("%d", &case_count);
    while(case_count --) {
        scanf("%d%s%d%s", &len1, gen1, &len2, gen2);
        init_memory(len1, len2);
        printf("%d\n", score(integer_array(gen1, len1), len1, 
                             integer_array(gen2, len2), len2));
    }
    return 0;
}

int max(int a, int b, int c) {
    return a < b ? max(b, c, a) : (a > c ? a : c);
}

void init_memory(int len1, int len2) {
    int i, j;
    for(i = 0; i <= len1; i ++) {
        for(j = 0; j <= len2; j ++) {
            memory[i][j] = INFINITE;
        }
    }
    memory[0][0] = 0;
}

int* integer_array(char* gen, int len) {
    int* array = (int*)malloc(sizeof(int)*len);
    int i;
    for(i = 0; i < len; i ++) {
        switch(gen[i]) {
            case 'A': array[i] = 0; break;
            case 'C': array[i] = 1; break;
            case 'G': array[i] = 2; break;
            case 'T': array[i] = 3; break;
        }
    }

    return array;
}

int score(int* gen1, int len1, int* gen2, int len2) {
    int max_score = 0, i;

    if(memory[len1][len2] != INFINITE) return memory[len1][len2];

    if(len1 > 0 && len2 > 0) {
        max_score = max(
                        score(gen1 + 1, len1 - 1, gen2 + 1, len2 - 1) + score_board[gen1[0]][gen2[0]],
                        score(gen1, len1, gen2 + 1, len2 - 1) + score_board[MINUS][gen2[0]],
                        score(gen1 + 1, len1 - 1, gen2, len2) + score_board[gen1[0]][MINUS]
                       );        
    } else if (len1 == 0 && len2 > 0) {
        for(i = 0; i < len2; i ++) {
            max_score += score_board[MINUS][gen2[i]];
        }   
    } else if (len2 == 0 && len1 > 0) {
        for(i = 0; i < len1; i ++) {
            max_score += score_board[gen1[i]][MINUS];
        }
    } 
    
    memory[len1][len2] = max_score;

    return max_score;
}