HDU 2844 Coins (Multi-pack counting space Change time)

Coins Time limit:2000/1000 MS (java/others) Memory limit:32768/32768 K (java/others) Total Submission (s): 8999 Accepted Submission (s): 3623
problem DescriptionWhuacmers use coins. They has coins of value a1,a2,a3 ... An Silverland dollar. One day Hibix opened purse and found there were some coins. He decided to buy a very nice watch at a nearby shop. He wanted to pay the exact price (without change) and he known the price would not more than m.but he didn ' t know the exact Price of the watch.

You is to write a program which reads N,M,A1,A2,A3 ... An AND c1,c2,c3 ... Cn corresponding to the number of Tony ' s coins of value a1,a2,a3 ... An and calculate how many prices (Form 1 to m) Tony can pay use these coins. InputThe input contains several test cases. The first line of all test case contains, integers n (1≤n≤100), M (m≤100000). The second line contains 2n integers, denoting a1,a2,a3 ... An,c1,c2,c3 ... Cn (1≤ai≤100000,1≤ci≤1000). The last test was followed by the zeros.  OutputThe For each test case output The answer to a single line. Sample Input

3 101 2 4 2 1 12 51 4 2 10 0

 Sample Output

84

 Sourcemulti-university Training Contest 3-host by WHU

Title Link: http://acm.hdu.edu.cn/showproblem.php?pid=2844

The main topic: N Kinds of numbers, each number of the value of AI, there are CI, how many can be composed of not more than m of different numbers

Topic Analysis: The data volume of the problem is really moving, three-layer loop (enumeration type, enumeration value, enumeration number) must time out, to find a way to subtract a layer of loops, careful analysis can be found that the number of the layer of the cycle can be omitted, the cost is to spend more space, open a CNT array record the current number of I used, The other two-layer loop is constant, then the normal backpack counting problem

#include <cstdio> #include <cstring>int const MAXM = 1e5 + 5;int Const MAXN = 1e2 + 5;bool dp[maxm];int Cnt[max M];int A[MAXN], c[maxn];int  main () {    int n, m;    while (scanf ("%d%d", &n, &m)! = EOF && (n + m))    {        memset (DP, FALSE, sizeof (DP));        for (int i = 1; I <= n; i + +)            scanf ("%d", &a[i]);        for (int i = 1; I <= n; i + +)            scanf ("%d", &c[i]);        Dp[0] = true;        int ans = 0;        for (int i = 1; I <= n; i + +)        {            memset (CNT, 0, sizeof (CNT));            for (int s = a[i]; s <= m; s + +)            {                if (!dp[s] && dp[s-a[i] [&& Cnt[s-a[i]] < c[i])                {                    Dp[s] = true;                    Ans + +;                    Cnt[s] = Cnt[s-a[i]] + 1;        }} printf ("%d\n", ans);}    }

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HDU 2844 Coins (Multi-pack counting space Change time)