#include <iostream> #include <stdio.h> using namespace std; const int GL = 21; int d[1000000]; int war[1000000]; int kt2[GL][1000000]; int sum2[GL][1000000]; int mini2[GL][1000000]; int n, m; pair<int, int> get_mini(int pos, int len) { len--; int cur_sum = war[pos]; int cur_mini = min(0, cur_sum); int cur_pos = pos; for (int i = 0; i < GL; i++) { if (len & 1) { cur_sum -= war[cur_pos]; cur_mini = min(cur_mini, cur_sum + mini2[i][cur_pos]); cur_sum += sum2[i][cur_pos]; cur_pos = ((1ll << i) * (long long) n + cur_pos) % m; } len >>= 1; } return make_pair(cur_mini, cur_sum); } int get_mini_first(int pos, int len) { len--; int cur_sum = war[pos]; int cur_mini = min(0, cur_sum); int cur_pos = pos; for (int i = 0; i < GL; i++) { if (len & 1) { cur_sum -= war[cur_pos]; cur_mini = min(cur_mini, cur_sum + mini2[i][cur_pos]); cur_sum += sum2[i][cur_pos]; cur_pos = ((1ll << i) * (long long) n + cur_pos) % m; } len >>= 1; } return cur_mini; } long long min_res = 9223372036854775807ll; long long bin_search(const int pos) { const int posm = pos % m; pair<int, int> cykl = get_mini(posm, m); if (cykl.first + d[pos] > 0 && cykl.second >= 0) return 99999999999999ll; long long iCykli = 0; if (cykl.first + d[pos] > 0) { iCykli = max(0ll, ((long long)cykl.first + (long long)d[pos] - 1) / ((long long)-cykl.second) + 1); d[pos] += (long long)iCykli * (long long)cykl.second; } if ((long long)iCykli * (long long)m * (long long) n + (long long) pos + 1 > min_res) return (long long)iCykli * (long long)m; int imin = 1; int imax = 1000005ll; while (imin < imax) { int imid = (imin + imax) / 2; if (get_mini_first(posm, imid) + d[pos] > 0) imin = imid + 1; else imax = imid; } return imax - 1 + (long long)iCykli * (long long)m; } int main() { scanf("%d", &n); for (int i = 0; i < n; i++) scanf("%d", &d[i]); scanf("%d", &m); char ciag[m + 1]; scanf("%s", ciag); for (int i = 0; i < m; i++) war[i] = (ciag[i] == 'W' ? 1 : -1); for (int i = 0; i < m; i++) { kt2[0][i] = (i + n) % m; } for (int j = 1; j < GL; j++) { for (int i = 0; i < m; i++) { kt2[j][i] = kt2[j - 1][kt2[j - 1][i]]; } } for (int i = 0; i < m; i++) { sum2[0][i] = war[i] + war[kt2[0][i]]; } for (int j = 1; j < GL; j++) { for (int i = 0; i < m; i++) { sum2[j][i] = sum2[j - 1][i] + sum2[j - 1][kt2[j - 1][i]] - war[kt2[j - 1][i]]; } } for (int i = 0; i < m; i++) { mini2[0][i] = min(0, min(war[i], war[i] + war[kt2[0][i]])); } for (int j = 1; j < GL; j++) { for (int i = 0; i < m; i++) { mini2[j][i] = min(mini2[j - 1][i], mini2[j - 1][kt2[j - 1][i]] + sum2[j - 1][i] - war[kt2[j - 1][i]]); } } // 9999999999999 for (int i = 0; i < n; i++) { long long b_s = bin_search(i); if (b_s != 99999999999999) min_res = min(min_res, b_s * (long long) n + (long long) i + 1); } if (min_res == 9223372036854775807ll) { printf("-1"); } else { printf("%lld\n", min_res); } return 0; }
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 | #include <iostream> #include <stdio.h> using namespace std; const int GL = 21; int d[1000000]; int war[1000000]; int kt2[GL][1000000]; int sum2[GL][1000000]; int mini2[GL][1000000]; int n, m; pair<int, int> get_mini(int pos, int len) { len--; int cur_sum = war[pos]; int cur_mini = min(0, cur_sum); int cur_pos = pos; for (int i = 0; i < GL; i++) { if (len & 1) { cur_sum -= war[cur_pos]; cur_mini = min(cur_mini, cur_sum + mini2[i][cur_pos]); cur_sum += sum2[i][cur_pos]; cur_pos = ((1ll << i) * (long long) n + cur_pos) % m; } len >>= 1; } return make_pair(cur_mini, cur_sum); } int get_mini_first(int pos, int len) { len--; int cur_sum = war[pos]; int cur_mini = min(0, cur_sum); int cur_pos = pos; for (int i = 0; i < GL; i++) { if (len & 1) { cur_sum -= war[cur_pos]; cur_mini = min(cur_mini, cur_sum + mini2[i][cur_pos]); cur_sum += sum2[i][cur_pos]; cur_pos = ((1ll << i) * (long long) n + cur_pos) % m; } len >>= 1; } return cur_mini; } long long min_res = 9223372036854775807ll; long long bin_search(const int pos) { const int posm = pos % m; pair<int, int> cykl = get_mini(posm, m); if (cykl.first + d[pos] > 0 && cykl.second >= 0) return 99999999999999ll; long long iCykli = 0; if (cykl.first + d[pos] > 0) { iCykli = max(0ll, ((long long)cykl.first + (long long)d[pos] - 1) / ((long long)-cykl.second) + 1); d[pos] += (long long)iCykli * (long long)cykl.second; } if ((long long)iCykli * (long long)m * (long long) n + (long long) pos + 1 > min_res) return (long long)iCykli * (long long)m; int imin = 1; int imax = 1000005ll; while (imin < imax) { int imid = (imin + imax) / 2; if (get_mini_first(posm, imid) + d[pos] > 0) imin = imid + 1; else imax = imid; } return imax - 1 + (long long)iCykli * (long long)m; } int main() { scanf("%d", &n); for (int i = 0; i < n; i++) scanf("%d", &d[i]); scanf("%d", &m); char ciag[m + 1]; scanf("%s", ciag); for (int i = 0; i < m; i++) war[i] = (ciag[i] == 'W' ? 1 : -1); for (int i = 0; i < m; i++) { kt2[0][i] = (i + n) % m; } for (int j = 1; j < GL; j++) { for (int i = 0; i < m; i++) { kt2[j][i] = kt2[j - 1][kt2[j - 1][i]]; } } for (int i = 0; i < m; i++) { sum2[0][i] = war[i] + war[kt2[0][i]]; } for (int j = 1; j < GL; j++) { for (int i = 0; i < m; i++) { sum2[j][i] = sum2[j - 1][i] + sum2[j - 1][kt2[j - 1][i]] - war[kt2[j - 1][i]]; } } for (int i = 0; i < m; i++) { mini2[0][i] = min(0, min(war[i], war[i] + war[kt2[0][i]])); } for (int j = 1; j < GL; j++) { for (int i = 0; i < m; i++) { mini2[j][i] = min(mini2[j - 1][i], mini2[j - 1][kt2[j - 1][i]] + sum2[j - 1][i] - war[kt2[j - 1][i]]); } } // 9999999999999 for (int i = 0; i < n; i++) { long long b_s = bin_search(i); if (b_s != 99999999999999) min_res = min(min_res, b_s * (long long) n + (long long) i + 1); } if (min_res == 9223372036854775807ll) { printf("-1"); } else { printf("%lld\n", min_res); } return 0; } |