Minimum Expression of String 字符串最小表示

　　十分详细的解释：http://hi.baidu.com/kfkkwlhvxcadotr/item/14a46a2b1f889e152a0f1c5f

几道相关例题的代码：

#include <cstdio>
#include <cstring>
#include <cassert>
#include <algorithm>

using namespace std;

char buf[100001];

int minExp(char *s) {
    int i = 0, j = 1, k = 0, t;
    int len = strlen(s);

    while (i < len && j < len && k < len) {
        t = s[(i + k) % len] - s[(j + k) % len];
        if (!t) {
            k++;
        } else {
            if (t > 0) i = i + k + 1;
            else {
                j = j + k + 1;
            }
            if (i == j) j++;
            k = 0;
        }
//printf("%d %d %d\n", i, j, k);
    }

    return min(i, j);
}

int main() {
    int T, n;

    scanf("%d", &T);
    while (T-- && ~scanf("%d %s", &n, buf)) {
        printf("%d\n", minExp(buf));
        memset(buf, 0, sizeof(buf));
    }

    return 0;
}

#include <cstdio>
#include <cstring>
#include <cassert>
#include <algorithm>

using namespace std;

char buf[10001];

int minExp(char *s) {
    int i = 0, j = 1, k = 0, t;
    int len = strlen(s);

    while (i < len && j < len && k < len) {
        t = s[(i + k) % len] - s[(j + k) % len];
        if (!t) {
            k++;
        } else {
            if (t > 0) i = i + k + 1;
            else {
                j = j + k + 1;
            }
            if (i == j) j++;
            k = 0;
        }
//printf("%d %d %d\n", i, j, k);
    }

    return min(i, j) + 1;
}

int main() {
    int T;

    scanf("%d", &T);
    while (T-- && ~scanf("%s", buf)) {
        printf("%d\n", minExp(buf));
        memset(buf, 0, sizeof(buf));
    }

    return 0;
}

#include <cstdio>
#include <cstring>
#include <cassert>
#include <algorithm>
#include <set>
#include <string>

using namespace std;

set<string> cnt;
char buf[101];

int minExp(char *s) {
    int i = 0, j = 1, k = 0, t;
    int len = strlen(s);

    while (i < len && j < len && k < len) {
        t = s[(i + k) % len] - s[(j + k) % len];
        if (!t) {
            k++;
        } else {
            if (t > 0) i = i + k + 1;
            else {
                j = j + k + 1;
            }
            if (i == j) j++;
            k = 0;
        }
//printf("%d %d %d\n", i, j, k);
    }

    return min(i, j);
}

void con(char *a){
    int pos = minExp(a);
    int len = strlen(a);
    char tmp[101];
    
    strcpy(tmp, a);
    for (int i = 0; i < len; i++){
        a[i] = tmp[(pos + i) % len];
    }
}

int deal(int n){
    cnt.clear();
    for (int i = 0; i < n; i++){
        scanf("%s", buf);
        con(buf);
        cnt.insert(buf);
    }

    return cnt.size();
}

int main(){
    int n;

    while (~scanf("%d", &n)){
        printf("%d\n", deal(n));
    }

    return 0;
}

#include <cstdio>
#include <cstring>
#include <cassert>
#include <algorithm>
#include <set>
#include <string>

using namespace std;

set<string> cnt;
char buf[300001], tmp[300001];

int minExp(char *s) {
    int i = 0, j = 1, k = 0, t;
    int len = strlen(s);

    while (i < len && j < len && k < len) {
        t = s[(i + k) % len] - s[(j + k) % len];
        if (!t) {
            k++;
        } else {
            if (t > 0) i = i + k + 1;
            else {
                j = j + k + 1;
            }
            if (i == j) j++;
            k = 0;
        }
//printf("%d %d %d\n", i, j, k);
    }

    return min(i, j);
}

void work() {
    int len = strlen(buf);

    tmp[0] = (buf[0] - buf[len - 1] + 8) % 8 + '0';
    for (int i = 1; i < len; i++){
        tmp[i] = (buf[i] - buf[i - 1] + 8) % 8 + '0';
    }

    int pos = minExp(tmp);

    for (int i = 0; i < len; i++) {
        buf[i] = tmp[(pos + i) % len];
    }
}

int main() {
    while (~scanf("%s", buf)) {
        work();
        printf("%s\n", buf);
    }

    return 0;
}

 

——written by Lyon