【POJ】1505 Copying Books

此题主要采用DP思路，难点是求解"/"，需要考虑划分数量不够的情况，先采用DP求解最优解，然后采用贪心求解slash。防止中间结果出错，使用了unsigned int。

#include <iostream>
using namespace std;

#define MAXNUM 501

unsigned int pages[MAXNUM][MAXNUM];

int main() {
    int case_n, m, k;
    int i, j, p, q;
    unsigned min, tmp, sum;

    cin >>case_n;

    for (p=1; p<=case_n; ++p) {
        cin >>m>>k;
        for (i=1; i<=m; ++i)
            cin >>pages[0][i];

        // handle the One worker case
        pages[1][1] = pages[0][1];
        for (i=2; i<=m ;++i)
            pages[1][i] = pages[0][i] + pages[1][i-1];

        for (i=2; i<=k; i++) {
            for (j=1; j<=m; j++) {
                if (i>j) {
                    pages[i][j] = pages[i-1][j];
                } else {
                    min = pages[i-1][j];
                    sum = 0;
                    for (q=j-1; q>=i-1; q--) {
                        sum += pages[0][q+1];
                        tmp = (sum > pages[i-1][q]) ? sum : pages[i-1][q];
                        if (tmp <= min)
                            min = tmp;
                        else
                            break;
                    }
                    pages[i][j] = min;
                }
            }
        }

        bool slash[MAXNUM] = {false};
        int slash_num = 0;
        sum = 0;
        for (i=m; i>=1; i--) {
            if (sum + pages[0][i] > pages[k][m]) {
                slash[i] = true;
                slash_num++;
                sum = pages[0][i];
            } else {
                sum += pages[0][i];
            }
        }
        if (slash_num < k-1) {
            for (i=1; i<=m && slash_num != k-1; i++) {
                if ( !slash[i] ) {
                    slash[i] = true;
                    slash_num++;
                }
            }
        }

        for (i=1; i<m; i++) {
            cout <<pages[0][i];
            if (slash[i])
                cout <<" / ";
            else
                cout <<" ";
        }
        cout <<pages[0][m]<<endl;
    }

    return 0;
}