uva_cpp_clean/10069/10069-21.cpp

/*
  >>~~ UVa Online Judge ACM Problem Solution ~~<<

  ID: 10069
  Name: Distinct Subsequences
  Problem: https://onlinejudge.org/external/100/10069.pdf
  Language: C++

  Author: Arash Shakery
  Email: [email protected]
*/

#include <math.h>
#include <stdio.h>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <iomanip>
#include <vector>
using namespace std;

class BigInt {
    typedef int CellType;
    const static int CellSize = sizeof(CellType);
    const static int MAX_C = 10000;
    const static int MAX_D = 4;
    CellType *cells;
    int capacity, size, sign;

    int sgn(int x) {
        return x<0 ? -1 : x>0 ? 1 : 0;
    }

    void init() {
        sign = size = 0;
        cells = new CellType[capacity = 100];
        memset(cells, 0, 4*CellSize);
    }

    int setSize(int sz, bool cp = true) {
        return size = sz;
    }

    BigInt& autoSize() {
        while (size>0 && !cells[size-1])
            size--;
        if (!size) sign=0;
        return *this;
    }

    public:
    BigInt() { init(); }
    BigInt(int x) {
        init();
        sign = sgn(x); x*=sign;
        for (size=0; x; size++) {
            cells[size] = x % MAX_C;
            x /= MAX_C;
        }
    }
    BigInt(const BigInt& o): cells(0), capacity(0) {
        init();
        sign = o.sign;
        setSize(o.size, 0);
        for (int i=0; i<size; i++)
            cells[i] = o.cells[i];
    }

    ~BigInt() {
        if (capacity >= 0)
            delete [] cells;
    }

    public:
    void setZero() {
        sign = size = cells[0] = 0;
    }
    void setOne() {
        sign = size = cells[0] = 1;
    }
    bool isZero() {
        return sign==0;
    }

    BigInt& operator=(const BigInt &o) {
        sign = o.sign;
        size = o.size;
        for (int i=0; i<size; i++)
            cells[i] = o.cells[i];
        return *this;
    }

    BigInt& operator+= (BigInt o) {
        if (!o.sign) return *this;
        if (!sign) sign = o.sign;

        for (int i=size; i<o.size+1; i++)
            cells[i] = 0;

        setSize(max(size, o.size)+1);
        for (int i=0; i<o.size; i++)
            if ( (cells[i] += o.cells[i]) >= MAX_C ) {
                cells[i] -= MAX_C;
                cells[i+1]++;
            }
        return autoSize();
    }
    // ---------------------------------------------------------------------
    friend std::ostream& operator<< (std::ostream& stream, const BigInt& bs) {
        if (!bs.sign)
            stream << 0;
        else {
            if (bs.sign < 0) stream << '-';
            stream << bs.cells[bs.size-1];
            for (int i=bs.size-2; i>=0; i--)
                stream << setfill('0') << setw(MAX_D) << bs.cells[i];
        }
        return stream;
    }
};


char s1[10016], s2[117];
BigInt DP[10017][103];
int main(){
    int T;
    scanf("%d", &T);
    while (T--) {
        scanf("%s%s", s1, s2);
        int l1=strlen(s1), l2=strlen(s2);

        if (l1 < l2) puts("0");
        else {
            for (int i=0; i<l1; i++) {
                DP[i][0].setOne();
                for (int j=0; j<l2; j++) {
                    DP[i+1][j+1] = DP[i][j+1];
                    if (s1[i] == s2[j])
                        DP[i+1][j+1] += DP[i][j];
                }
            }

            cout << DP[l1][l2] << endl;
        }
    }
}