#include <cstdio> #include <cstdlib> const int NN = 50500; struct Dist { int size; int threat; }; struct Map { Dist dists[NN]; int length; }theMap; inline int _max(int a, int b) { if (a > b) { return a; } else { return b; } } Map *parse(char *str) { Map *r = &theMap; int count = 0; int threat = 0; int len = 0; for (; *str; ++str) { if (*str == '1') { if (len > 0) { r->dists[count++] = {.size = len, .threat = threat + 1}; len = 0; } threat = 1; } else { ++len; } } if (len > 0) { r->dists[count++] = {.size = len, .threat = threat}; } r->length = count; return r; } int dist_a_cmp(const void *a, const void *b) { return (*(const Dist **)b)->size - (*(const Dist **)a)->size; } int pan(Map *map) { const int len = map->length; Dist *low[2]; Dist *dists[NN]; int lows = 0; int offset = 0; int postset = 0; int max = 0; int saved; int time; int place; for (int i = 0; i < len; ++i) { dists[i] = map->dists + i; } Dist *x; if (len > 0) { x = dists[0]; if (x->threat == 1 && x->size > 1) { low[lows++] = x; ++offset; } } if (len - offset > 0) { x = dists[len - 1]; if (x->threat == 1 && x->size > 1) { low[lows++] = x; ++postset; } } qsort(dists, len, sizeof(Dist *), dist_a_cmp); qsort(low, lows, sizeof(Dist *), dist_a_cmp); for (int cheat = 0; cheat < 3 && cheat <= lows; ++cheat) { saved = 0; time = 0; place = 0; for (int l = 0; l < lows; ++l) { low[l]->threat = 1; } for (; time < cheat; ++time) { saved += low[time]->size - time; low[time]->threat = -1; } for (; place < len; ++place) { Dist *curr = dists[place]; if (curr->threat == 0) { saved = curr->size; break; } if (curr->threat == -1) { continue; } int left = curr->size - time * curr->threat - (curr->threat - 1); if (left == 0 && curr->threat == 2) { left = 1; } if (left <= 0) { break; } else { saved += left; time += curr->threat; } } max = _max(max, saved); } return max; } int main() { char str[100100]; int t, n; scanf("%d", &t); while (t--) { scanf("%d%s", &n, str); Map *m = parse(str); int result = n - pan(m); printf("%d\n", result); } 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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 | #include <cstdio> #include <cstdlib> const int NN = 50500; struct Dist { int size; int threat; }; struct Map { Dist dists[NN]; int length; }theMap; inline int _max(int a, int b) { if (a > b) { return a; } else { return b; } } Map *parse(char *str) { Map *r = &theMap; int count = 0; int threat = 0; int len = 0; for (; *str; ++str) { if (*str == '1') { if (len > 0) { r->dists[count++] = {.size = len, .threat = threat + 1}; len = 0; } threat = 1; } else { ++len; } } if (len > 0) { r->dists[count++] = {.size = len, .threat = threat}; } r->length = count; return r; } int dist_a_cmp(const void *a, const void *b) { return (*(const Dist **)b)->size - (*(const Dist **)a)->size; } int pan(Map *map) { const int len = map->length; Dist *low[2]; Dist *dists[NN]; int lows = 0; int offset = 0; int postset = 0; int max = 0; int saved; int time; int place; for (int i = 0; i < len; ++i) { dists[i] = map->dists + i; } Dist *x; if (len > 0) { x = dists[0]; if (x->threat == 1 && x->size > 1) { low[lows++] = x; ++offset; } } if (len - offset > 0) { x = dists[len - 1]; if (x->threat == 1 && x->size > 1) { low[lows++] = x; ++postset; } } qsort(dists, len, sizeof(Dist *), dist_a_cmp); qsort(low, lows, sizeof(Dist *), dist_a_cmp); for (int cheat = 0; cheat < 3 && cheat <= lows; ++cheat) { saved = 0; time = 0; place = 0; for (int l = 0; l < lows; ++l) { low[l]->threat = 1; } for (; time < cheat; ++time) { saved += low[time]->size - time; low[time]->threat = -1; } for (; place < len; ++place) { Dist *curr = dists[place]; if (curr->threat == 0) { saved = curr->size; break; } if (curr->threat == -1) { continue; } int left = curr->size - time * curr->threat - (curr->threat - 1); if (left == 0 && curr->threat == 2) { left = 1; } if (left <= 0) { break; } else { saved += left; time += curr->threat; } } max = _max(max, saved); } return max; } int main() { char str[100100]; int t, n; scanf("%d", &t); while (t--) { scanf("%d%s", &n, str); Map *m = parse(str); int result = n - pan(m); printf("%d\n", result); } return 0; } |