import java.util.*; public class SegmentTreeFast { // Modify the following 5 methods to implement your custom operations on the tree. // This example implements Add/Sum operations. Operations like Add/Max, Set/Max can also be implemented. int modifyOperation(int x, int y) { return x + y; } // query (or combine) operation int queryOperation(int leftValue, int rightValue) { return leftValue + rightValue; } int deltaEffectOnSegment(int delta, int segmentLength) { if (delta == getNeutralDelta()) return getNeutralDelta(); // Here you must write a fast equivalent of following slow code: // int result = delta; // for (int i = 1; i < segmentLength; i++) result = queryOperation(result, delta); // return result; return delta * segmentLength; } int getNeutralDelta() { return 0; } int getInitValue() { return 0; } // generic code int[] value; int[] delta; // delta[i] affects value[i], delta[2*i+1] and delta[2*i+2] int joinValueWithDelta(int value, int delta) { if (delta == getNeutralDelta()) return value; return modifyOperation(value, delta); } int joinDeltas(int delta1, int delta2) { if (delta1 == getNeutralDelta()) return delta2; if (delta2 == getNeutralDelta()) return delta1; return modifyOperation(delta1, delta2); } void pushDelta(int i) { int d = 0; for (; (i >> d) > 0; d++) { } for (d -= 2; d >= 0; d--) { int x = i >> d; value[x >> 1] = joinNodeValueWithDelta(x >> 1, 1 << (d + 1)); delta[x] = joinDeltas(delta[x], delta[x >> 1]); delta[x ^ 1] = joinDeltas(delta[x ^ 1], delta[x >> 1]); delta[x >> 1] = getNeutralDelta(); } } public SegmentTreeFast(int n) { value = new int[2 * n]; for (int i = 0; i < n; i++) { value[i + n] = getInitValue(); } for (int i = 2 * n - 1; i > 1; i -= 2) { value[i >> 1] = queryOperation(value[i], value[i ^ 1]); } delta = new int[2 * n]; Arrays.fill(delta, getNeutralDelta()); } int joinNodeValueWithDelta(int i, int len) { return joinValueWithDelta(value[i], deltaEffectOnSegment(delta[i], len)); } public int query(int from, int to) { from += value.length >> 1; to += value.length >> 1; pushDelta(from); pushDelta(to); int res = 0; boolean found = false; for (int len = 1; from <= to; from = (from + 1) >> 1, to = (to - 1) >> 1, len <<= 1) { if ((from & 1) != 0) { res = found ? queryOperation(res, joinNodeValueWithDelta(from, len)) : joinNodeValueWithDelta(from, len); found = true; } if ((to & 1) == 0) { res = found ? queryOperation(res, joinNodeValueWithDelta(to, len)) : joinNodeValueWithDelta(to, len); found = true; } } if (!found) throw new RuntimeException(); return res; } public void modify(int from, int to, int delta) { from += value.length >> 1; to += value.length >> 1; pushDelta(from); pushDelta(to); int a = from; int b = to; for (; from <= to; from = (from + 1) >> 1, to = (to - 1) >> 1) { if ((from & 1) != 0) { this.delta[from] = joinDeltas(this.delta[from], delta); } if ((to & 1) == 0) { this.delta[to] = joinDeltas(this.delta[to], delta); } } for (int i = a, len = 1; i > 1; i >>= 1, len <<= 1) { value[i >> 1] = queryOperation(joinNodeValueWithDelta(i, len), joinNodeValueWithDelta(i ^ 1, len)); } for (int i = b, len = 1; i > 1; i >>= 1, len <<= 1) { value[i >> 1] = queryOperation(joinNodeValueWithDelta(i, len), joinNodeValueWithDelta(i ^ 1, len)); } } // Random test public static void main(String[] args) { Random rnd = new Random(); for (int step = 0; step < 1000; step++) { int n = rnd.nextInt(50) + 1; int[] x = new int[n]; SegmentTreeFast t = new SegmentTreeFast(n); Arrays.fill(x, t.getInitValue()); for (int i = 0; i < 1000; i++) { int b = rnd.nextInt(n); int a = rnd.nextInt(b + 1); int cmd = rnd.nextInt(3); if (cmd == 0) { int delta = rnd.nextInt(100) - 50; t.modify(a, b, delta); for (int j = a; j <= b; j++) { x[j] = t.joinValueWithDelta(x[j], delta); } } else if (cmd == 1) { int res1 = t.query(a, b); int res2 = x[a]; for (int j = a + 1; j <= b; j++) { res2 = t.queryOperation(res2, x[j]); } if (res1 != res2) { throw new RuntimeException(); } } else { for (int j = 0; j < n; j++) { if (t.query(j, j) != x[j]) { throw new RuntimeException(); } } } } } System.out.println("Test passed"); } }