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#include <stdlib.h>
#include <stdio.h>

#include "message.h"
#include "teatr.h"

#define LL long long
#define DBG(X)

class RangeSum {
    LL** bucket_;
    int bucketsCount_;

    LL* bucketSum_;
    LL totalSum_;

    int maxValue_;
public:

    RangeSum(int maxValue) {
        bucketsCount_ = (maxValue / 1024) + 2;
        bucket_ = new LL*[bucketsCount_];
        for (int i=0; i < bucketsCount_; i++) {
            bucket_[i] = new LL[1024];
        }
        bucketSum_ = new LL[bucketsCount_];
        for (int i=0; i < bucketsCount_; i++) {
            bucketSum_[i] = 0LL;
        }
        totalSum_ = 0;
        DBG(printf("Allocation OK\n"));
    }

    void increment(unsigned int key) {
        unsigned int bucketId = (key >> 10); // / 1024
        unsigned int bucketKey = (key & 0x3FF); // % 1024
        ++bucket_[bucketId][bucketKey];
        ++bucketSum_[bucketId];
        ++totalSum_;
    }

    LL countGreaterThan(unsigned int key) {
        unsigned int bucketId = (key >> 10); // / 1024
        unsigned int bucketKey = (key & 0x3FF); // % 1024
        LL res = 0;
        if (bucketKey >= 512) {
            for (unsigned int i=bucketKey+1; i < 1024; i++) {
                res += bucket_[bucketId][i];
            }
        }
        else {
            LL lessThanSum = 0;
            for (int i=bucketKey; i >=0; --i) {
                lessThanSum += bucket_[bucketId][i];
            }
            res += (bucketSum_[bucketId] - lessThanSum);
        }

        if (bucketId >= 512) {
            for (unsigned int i=bucketId+1; i < bucketsCount_; i++) {
                res += bucketSum_[i];
            }
        } else {
            LL bucketSumLessThanSum = 0;
            for (int i=bucketId; i >= 0; --i) {
                bucketSumLessThanSum += bucketSum_[i];
            }
            res += (totalSum_ - bucketSumLessThanSum);
        }

        return res;
    }

    void verifyInput(unsigned int key) {
        if (key > maxValue_) {
            printf("Too large key value: %u (max is %d)", key, maxValue_);
        }
    }
};

#if 0

void selftest_assert(LL x, LL y) {
    if (x != y) {
        printf("test: expected %lld, has: %lld\n", x, y);
    } else {
        printf("OK (%lld==%lld)\n", x, y);
    }
}

void test_rangeSum() {
    RangeSum rs(1000000);
    rs.increment(3);
    rs.increment(5);
    rs.increment(100);
    
    selftest_assert(3, rs.countGreaterThan(0));
    selftest_assert(2, rs.countGreaterThan(4));
    selftest_assert(1, rs.countGreaterThan(5));
    selftest_assert(0, rs.countGreaterThan(100));

    rs.increment(100000);
    rs.increment(200000);
    rs.increment(300000);

    selftest_assert(6, rs.countGreaterThan(0));
    selftest_assert(0, rs.countGreaterThan(300000));
    selftest_assert(2, rs.countGreaterThan(199999));

    rs.increment(1024);
    rs.increment(2048);
    rs.increment(1024);

    selftest_assert(4, rs.countGreaterThan(1024));
    selftest_assert(6, rs.countGreaterThan(1023));
}

int main_local() {
    

    return 0;
}

//#define TEST_F1 out: 2499912950050000
#ifdef TEST_F1 
int GetN() { return int(1e8); }
int GetElement(int i) { return (i * 1ll * i) % int(1e6) + 1; }
#endif

#define TEST_F2 Out: 2497220719002543
#ifdef TEST_F2 
int GetN() { return 100 * 1000 * 1000; }
int GetElement(int i) { 
return 1 + (((LL)i * 27) + i & (i %113) + ((i % 37) ^ (i % 20)) * 3571) % 1000000LL;
}
#endif

//#define TEST_F3 out: 299999394
#ifdef TEST_F3
int GetN() { return 100 * 1000 * 1000; }
int GetElement(int i) { 
if (i < 100 * 1000 * 1000 - 3) return 1 + i / 100;
else return 100 * 1000 * 1000 - i;
}
#endif
#endif // if 0

int main() {
    int length = GetN();
    int nid = MyNodeId();
    int numberOfNodes = NumberOfNodes();
    
    int MAX_K = 1000010;

    RangeSum rs(MAX_K);
    LL totalLocal = 0;
    for (int i=0; i < length; i++) {
        int val = GetElement(i);
        rs.increment(val);
        if (i % numberOfNodes == nid) {
            totalLocal += rs.countGreaterThan(val);
        }
    }

    if (nid > 0) {
        // send to the master node
        PutLL(0, totalLocal);
        Send(0);
    } else { // master node
        LL totalAllInstances = totalLocal;
        // wait for all other instances...
        for (int node=1; node < numberOfNodes; node++) {
            Receive(node);
            LL totalFromNode = GetLL(node);
            totalAllInstances += totalFromNode;
        }
        printf("%lld\n", totalAllInstances);
    }
    DBG(printf("%lld\n", totalLocal));

    return 0;
}