hdu 1053 Entropy

来源：互联网发布：linux crontab 权限编辑：程序博客网时间：2024/05/21 09:26
原题链接：http://acm.hdu.edu.cn/showproblem.php?pid=1053
哈弗曼编码。。
#include<algorithm>#include<iostream>#include<cstdlib>#include<cstring>#include<cstdio>#include<string>#include<queue>#include<set>using std::set;using std::sort;using std::swap;using std::string;using std::priority_queue;#define pb(e) push_back(e)#define sz(c) (int)(c).size()#define mp(a, b) make_pair(a, b)#define all(c) (c).begin(), (c).end()#define iter(c) decltype((c).begin())#define cls(arr, val) memset(arr, val, sizeof(arr))#define cpresent(c, e) (find(all(c), (e)) != (c).end())#define rep(i, n) for(int i = 0; i < (int)n; i++)#define tr(c, i) for(iter(c) i = (c).begin(); i != (c).end(); ++i)const int N = 30;const int INF = 0x3f3f3f3f;typedef unsigned long long ull;char buf[11000];struct Node {    char dat;    int w;    Node *ch[2];    Node(char _dat_, int _w_, Node *l = NULL, Node *r = NULL) {        dat = _dat_, w = _w_;        ch[0] = l, ch[1] = r;    }    Node(const Node &x) {        dat = x.dat, w = x.w;        ch[0] = x.ch[0], ch[1] = x.ch[1];    }    inline bool operator<(const Node &x) const {        return w > x.w;    }};struct Hoffmancode {    int sum;    Node *root;    priority_queue<Node> q;    inline char to_lower(char ch) {            return ch >= 'A' && ch <= 'Z' ? ch + 32 : ch;    }    inline void CreateHoffmanTree() {        Node *l = NULL, *r = NULL;        while (!q.empty() && q.size() != 1) {            l = new Node(q.top()); q.pop();            r = new Node(q.top()); q.pop();            Node ret(0, l->w + r->w, l, r);            q.push(ret);        }        if (!q.empty()) {            root = new Node(q.top()); q.pop();        }    }    inline void CreateHoffmanCode(Node *x, string str) {        if (!x) return;        if (x->dat != 0) {            sum += (str.length() * x->w);        }        CreateHoffmanCode(x->ch[0], str + "0");        CreateHoffmanCode(x->ch[1], str + "1");    }    inline void solve() {        sum = 0, root = NULL;        int arr[N] = { 0 }, tot = 0, n = strlen(buf);        while (!q.empty()) q.pop();        for (int i = 0; i < n; i++) {            arr[to_lower(buf[i]) - '_']++;        }        for (int i = 0; i < 28; i++) {            if (arr[i]) {                tot++;                Node ret('_' + i, arr[i]);                q.push(ret);            }        }        if (1 == tot) {            printf("%d %d 8.0\n", n * 8, n);            return;        }        CreateHoffmanTree();        CreateHoffmanCode(root, "");        printf("%d %d %.1lf\n", n * 8, sum, (double)(n * 8) / sum);    }}work;int main() {#ifdef LOCAL    freopen("in.txt", "r", stdin);    freopen("out.txt", "w+", stdout);#endif    while (~scanf("%s", buf) && 0 != strcmp(buf, "END")) {        work.solve();    }    return 0;}
0 0