LRJ-Example-06-17-Uva10562

main() 函数中的这两行

fgets(buf[0], maxn, stdin);
sscanf(buf[0], "%d", &T);

不能简单替换为

scanf("%d", &T);

因为这会影响后面用fgets()读取数的内容。这个scanf之后调用 fgets() 会读取一个空的行。

从样例输出里面可以看到

每棵树的最外侧有一对()

每个叶子节点后面是()，代表空树

#include <cstdio>
#include <cstring>
#include <cctype>

using namespace std;

int n = ;
const int maxn =  + ;
char tree[maxn][maxn];

bool isLabel(char c) {
    if( c == '-' || c == '|' || c == ' ' || c == '#' || c == '\n') return false;
    else return true;
}

void dfs(int row, int col)
{
    printf("%c(", tree[row][col]);
    if(row+ < n && tree[row+][col] == '|') { // [row][col] has a subtree
        //
        if(row+ < n) { // ----
            // find leftmost '-' of this subtree
            int c = col;
            int l = strlen(tree[row+]);
            while(c- >=  && tree[row+][c-] == '-') c--;

            //printf("\nleftmost - is at [%d][%d]\n", row+2, c);

            for(int i = c; i < l && tree[row+][i] == '-'; i++) { // each child
                //if(row+3 < n && tree[row+3][i] != '\0' && !isspace(tree[row+3][i])) {
                if(row+ < n && isLabel(tree[row+][i]) && !isspace(tree[row+][i])) {
                    dfs(row+, i);
                }
            }
        }
    }
    printf(")");
}

void solve() {
    memset(tree, , sizeof(tree));
    n = ;
    while(true) {
        fgets(tree[n], maxn, stdin); // read each line
        if(tree[n][] == '#') break;
        n++;
    }

    /*
    for(int i = 0; i < n; i++) {
        printf("%s", tree[i]);
    }
    */

    printf("(");

    if(n > ) { // tree is not empty
        int col = ;
        int len = strlen(tree[]);
        //while(col < len && tree[0][col] == ' ') col++;

        //dfs(0, col); //root is at [0][col]
        for(int i = ; i < len; i++)
            if(tree[][i] != ' ') {
                dfs(, i);
                break;
            }
    }

    printf(")\n");
}

int main() {
    int T;
    fgets(tree[], maxn, stdin);
    sscanf(tree[], "%d", &T);
    while(T--) {
        solve();
    }
}

下面是 accept的代码

#include <cstdio>
#include <cstring>
#include <cctype>

using namespace std;

int n = ;
const int maxn =  + ;
char tree[maxn][maxn];

bool isLabel(char c) {
    if( c == '-' || c == '|' || c == ' ' || c == '#' || c == '\n') return false;
    else return true;
}

void dfs(int row, int col)
{
    printf("%c(", tree[row][col]);
    if(row+ < n && tree[row+][col] == '|') { // [row][col] has a subtree
        //
        if(row+ < n) { // ----
            // find leftmost '-' of this subtree
            int c = col;
            int l = strlen(tree[row+]);
            while(c- >=  && tree[row+][c-] == '-') c--;

            //printf("\nleftmost - is at [%d][%d]\n", row+2, c);

            for(int i = c; i < l && tree[row+][i] == '-'; i++) { // each child
                if(row+ < n && tree[row+][i] != '\0' && !isspace(tree[row+][i])) {
                //if(row+3 < n && isLabel(tree[row+3][i]) && !isspace(tree[row+3][i])) {
                    dfs(row+, i);
                }
            }
        }
    }
    printf(")");
}

void solve() {
    memset(tree, , sizeof(tree));
    n = ;
    while(true) {
        fgets(tree[n], maxn, stdin); // read each line
        if(tree[n][] == '#') break;
        n++;
    }

    /*
    for(int i = 0; i < n; i++) {
        printf("%s", tree[i]);
    }
    */

    printf("(");

    if(n > ) { // tree is not empty
        int col = ;
        int len = strlen(tree[]);
        //while(col < len && tree[0][col] == ' ') col++;

        //dfs(0, col); //root is at [0][col]
        for(int i = ; i < len; i++)
            if(tree[][i] != ' ') {
                dfs(, i);
                break;
            }
    }

    printf(")\n");
}

int main() {
    int T;
    fgets(tree[], maxn, stdin);
    sscanf(tree[], "%d", &T);
    while(T--) {
        solve();
    }
}