1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
#include <cstdio>
#include <cstring>
#include <list>

using namespace std;

int main()
{
    int n, m;
    scanf(" %d %d", &n, &m);

    int yeys[n];        //  outgoing
    std::memset(yeys, 0, sizeof yeys);

    int neighs[n];      //  incoming
    std::memset(neighs, 0, sizeof neighs);

    list<int> * inyeys = new list<int>[n];        // incoming
    list<int> * outneighs = new list<int>[n];     //  outgoing
    list<int> * all_yeys = new list<int>[n];        // incoming

    //  read requirements, fill out basic structures

    for (int i = 0; i<m; i++){
        int a, b;
        char c;
        scanf(" %d %d %c", &a, &b, &c);
        a-=1;
        b-=1;
        if (c == 'T') {
            inyeys[b].push_back(a);
            all_yeys[b].push_back(a);
            all_yeys[a].push_back(b);
            yeys[a] += 1;
        }
        else {
            outneighs[a].push_back(b);
            neighs[b] += 1;
        }
    }

    //  choose the root - no outgoing yeys, no incoming neighs, otherwise not possible: NIE

    int root = -1;
    for(int i = 0; i<n; i++){
        if (yeys[i] == 0 && neighs[i] == 0) {
            root = i;
            break;
        }
    }
    if (root == -1){
        printf("NIE\n");
        return 0;
    }

    //  update yeys and neighs in the remaining items
    for(list<int>::iterator it = outneighs[root].begin(); it != outneighs[root].end(); it++){
        neighs[*it] -= 1;
    }

    for(list<int>::iterator it = inyeys[root].begin(); it != inyeys[root].end(); it++){
        yeys[*it] -= 1;
    }



    int parents[n];
    std::memset(parents, -1, sizeof parents);

    parents[root] = 0;

    //  mark lineages (components connected by yeys)

    int lineage_count = 0;

    int lineage_ix[n];
    std::memset(lineage_ix, -1, sizeof lineage_ix);

    for(int i = 0; i<n; i++){
        if (lineage_ix[i] == -1){
            list<int> queue;
            queue.push_back(i);
            int debug = 0;
            while(!queue.empty()){
                int current = queue.front();
                queue.pop_front();
                if (lineage_ix[current] == -1){
                    lineage_ix[current] = lineage_count;
                    queue.insert(queue.begin(), all_yeys[current].begin(), all_yeys[current].end());
                }
            }
            lineage_count++;
        }
    }

    //  remove neighs across lineages

    for (int i = 0; i < n; i++){
        list<int> to_remove;
        for(list<int>::iterator it = outneighs[i].begin(); it != outneighs[i].end(); it++){
            if (lineage_ix[i] != lineage_ix[*it]) {
                to_remove.push_back(*it);
            }
        }

        for(list<int>::iterator it = to_remove.begin(); it != to_remove.end(); it++){
            outneighs[i].remove(*it);
            neighs[*it] -= 1;
        }
    }

    int lineages_parents[lineage_count];
    for (int i = 0; i < lineage_count; i++){
        lineages_parents[i] = root;
    }

    int lineages_empty = 0;
    while(lineages_empty < lineage_count){

    //  one per lineage:
        int chosen[lineage_count];
        std::memset(chosen, -1, sizeof chosen);

        bool empty[lineage_count];
        std::memset(empty, true, sizeof empty);

    //  choose and remove current children with no outgoing yeys, no incoming neighs otherwise not possible: NIE
        for(int i = 0; i < n; i++){
            if (parents[i] == -1 && chosen[lineage_ix[i]] == -1) {
                empty[lineage_ix[i]] = false;
                if (yeys[i] == 0 && neighs[i] == 0){
                    chosen[lineage_ix[i]] = i;
                }
            }
        }

    //  update it's parent and lineages_current
        lineages_empty = 0;
        for(int i = 0; i < lineage_count; i++){
            if (chosen[i] == -1){
                if (empty[i]) {
                    lineages_empty += 1;
                } else {
                    printf("NIE\n");
                    return 0;
                }
            } else {
                parents[chosen[i]] = lineages_parents[i];
                lineages_parents[i] = chosen[i];

                //  update yeys and neighs in the remaining items
                for(list<int>::iterator it = outneighs[chosen[i]].begin(); it != outneighs[chosen[i]].end(); it++){
                    if (*it != -1)
                        neighs[*it] -= 1;
                }

                for(list<int>::iterator it = inyeys[chosen[i]].begin(); it != inyeys[chosen[i]].end(); it++){
                    if (*it != -1)
                        yeys[*it] -= 1;
                }

            }
        }
    }


    for (int i = 0; i < n; i++){
        if (i == root)
            printf("0\n");
        else
            printf("%d\n", parents[i]+1);
    }

    return 0;
}